* [CVE-2026-80922][MODERATE REGULAR] crypto: qcom-rng - Allow zero as a random number
@ 2026-09-09 16:57 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-09 16:57 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-80922
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: crypto: qcom-rng - Allow zero as a random number
Commit: 813e6718a199befc4f26f54bdd899fbfa11515e5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=813e6718a199befc4f26f54bdd899fbfa11515e5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80922
Analysis date: Wed, 09 Sep 2026 12:57:24 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-80922 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80922
The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.
The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.
Published priority for this report: MODERATE REGULAR
Manual review required: YES
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-80922 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80922 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N';CWE-330;CWE-331;CWE-338;Other CVSS 'AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '4';DESCR 'qcom rng rejected a 32 bit value of zero from the hardware RNG and returned EINVAL even though zero is a valid random output. This conditions the output on being non zero and makes the stream statistically distinguishable from uniform random data, which can weaken entropy quality for consumers of this hwrng on affected Qualcomm platforms. For the CVSS the PR:N is used because an external attacker does not need local privileges on the target to benefit from weakened cryptographic randomness, but there is no direct local or network trigger that reliably forces the bad value. The issue is not directly network reachable. Impact is mainly a low confidentiality risk from biased randomness, with paranoid integrity impact possible if generated keys or protocol nonces depend on this source. YES REQUIRES MANUAL CHECK because RNG quality bugs are security sensitive even when the numeric score is low.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) SKIP CVE-2026-80922 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: f29cd5bb64c2 YES NO NO unknown MAYBE LINUS INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=3
ActionableScoreLower=2
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 3
* Paranoid score: 3
* Final recommended bucket: **Borderline / manual review recommended**::
No floor or cap changed the score.
2. Signal breakdown
Positive signals:
* +2: Concrete cryptographic RNG quality defect. The driver rejected a valid 32 bit zero output from the hardware RNG, conditioning the stream on non zero values and making it statistically distinguishable from uniform random data.
* +1 paranoid only: Security-sensitive downstream use is plausible. hwrng output may contribute to cryptographic keys, nonces, or entropy pools on affected Qualcomm platforms, so manual review is justified even though no concrete key recovery or protocol break is shown.
Non-awarded signals:
* +2 remote reachable not awarded. The vulnerable behavior is not a network packet-processing path and the attacker cannot directly force the device to emit zero.
* +1 local unprivileged trigger not awarded. No ordinary local user trigger of the exact bad condition is established.
* Memory corruption not awarded. No UAF, OOB, stale pointer, refcount misuse, or write primitive is present.
* Confidentiality/integrity exploit consequence not awarded as an ActionableScore signal. The patch establishes distinguishability and possible entropy weakening, not a demonstrated secret disclosure, key recovery, unauthorized modification, or privilege escalation.
* Reliable kernel crash / DoS not awarded. The bug is about rejecting a valid random value, not a panic or host-wide failure.
* Hardware rarity penalty not applied. Qualcomm hardware specificity alone is not enough for a negative score under the rules.
* Host-admin penalty not applied. The evidence does not prove that exploiting or benefiting from the weakened randomness requires host-admin-equivalent privilege.
3. Reachability analysis
The affected code is a Qualcomm hardware RNG driver read path. The bad condition occurs when the hardware returns a 32 bit value of zero, which is a valid random value but was incorrectly treated as an error. An attacker is not shown to control when this value appears, and no direct local or remote trigger is established.
The practical attacker model is indirect: an attacker may benefit if security-sensitive material on an affected platform is generated using randomness influenced by this biased hwrng output. That does not require proving host-admin privileges for the attacker, but the supplied evidence also does not establish a complete below-host-admin trigger chain. Therefore HostAdminRequired is UNKNOWN rather than YES or NO.
No namespace-scoped capability is involved. No prior privileged setup beyond using an affected platform and driver is established. No race or timing issue is present.
4. Primitive and severity interpretation
The exact primitive is not memory corruption. It is a cryptographic randomness quality flaw: valid zero outputs are discarded, so the output distribution is biased and distinguishable from uniform random data.
PrimitiveClass is NONE because there is no kernel corruption, lifetime violation, authorization bypass, ownership violation, or concrete disclosure/write primitive. The demonstrated consequence is reduced randomness quality. The speculative consequence is weakening of cryptographic operations that rely on this entropy source, but no concrete key recovery, nonce prediction, or privilege escalation path is supplied.
ImportantCandidate is NO because the patch does not establish a strong corruption, authorization, ownership, or demonstrated cryptographic break primitive. AutoDowngradeAllowed is YES under the strict scoring rules because no unresolved concrete kernel exploitation primitive remains, but manual review is still recommended because RNG correctness is security-sensitive.
Likely operational severity is low to borderline moderate, with higher concern for products where qcom-rng is a primary entropy source for cryptographic material.
5. One-sentence report phrase
qcom-rng incorrectly rejected zero as a valid hardware RNG output, making the random stream distinguishable from uniform data and potentially weakening cryptographic entropy on affected Qualcomm platforms.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Reason: no memory corruption or direct exploit primitive is established, but RNG output correctness can affect key, nonce, and entropy quality, so product-specific entropy usage should be reviewed before automatic closure.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: crypto: qcom-rng - Allow zero as a random number
Commit: 813e6718a199befc4f26f54bdd899fbfa11515e5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=813e6718a199befc4f26f54bdd899fbfa11515e5
Commit description:
Zero is a valid random number and needs to be allowed. Otherwise the
output is distinguishable from random.
Fixes: f29cd5b ("crypto: qcom-rng - Add hw_random interface support")
Cc: [email protected]
Reviewed-by: Dmitry Baryshkov <[email protected]>
Reviewed-by: Konrad Dybcio <[email protected]>
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
drivers/crypto/qcom-rng.c
Diff excerpt:
Not included in this email. See the upstream URL for the full patch.
Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=813e6718a199befc4f26f54bdd899fbfa11515e5
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-80922 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80922
The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.
The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.
The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.
Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:
Conservative CVSS vector: AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
The Best / paranoid CVSS vector: AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
The Best / paranoid CVSS score: 4
The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.
CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.
A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.
Conservative ActionableScore: 2
Paranoid ActionableScore: 3
The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.
For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:
ActionableScore below 5 -> MODERATE REGULAR
ActionableScore 5 or more -> MODERATE 7.0
The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.
There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).
KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.
AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR
These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).
Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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