From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-45988][MODERATE 7.0] rxrpc: Fix re-decryption of RESPONSE packets Date: Wed, 27 May 2026 12:23:43 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-45988 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: d61482be4aae1835b78875761206241835a7510e List-Id: CVE: CVE-2026-45988 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: rxrpc: Fix re-decryption of RESPONSE packets Commit: d61482be4aae1835b78875761206241835a7510e Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d61482be4aae1835b78875761206241835a7510e Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45988 Analysis date: Wed, 27 May 2026 12:23:43 -0400 ActionableScore: 5 ActionableScore lower bound: 3 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: RxRPC could requeue and reprocess a partially decrypted RESPONSE packet after a temporary error, corrupting secure protocol state and allowing remote connection disruption or DoS on reachable RxRPC services. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-45988 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45988 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 7.0 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-2026-45988 MODERATE CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';CWE-703;CWE-755;CWE-327;Other CVSS 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '7';DESCR 'RxRPC RESPONSE packet processing could requeue a packet after a temporary error even though it may already be partially decrypted. Retrying that same skb can decrypt it again and corrupt the protocol payload, leading to authentication failure, connection disruption, or DoS. For the CVSS the PR:N is used because a remote RxRPC peer can send CHALLENGE or RESPONSE traffic when the RxRPC service is reachable. AC:H is used because practical triggering also depends on temporary processing failures such as ENOMEM or EAGAIN. The issue is network reachable only for systems using RxRPC or AFS style services. No UAF, out of bounds write, arbitrary write, information disclosure, or privilege escalation is shown by the patch.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) YES INIT TRACE NOMEMCHK SIMPLEFIX SKB LINUS PACKET INCREASED_TO_MODERATE_FROM_LOW_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative signals: * Remote/network-triggerable: +2 RxRPC packets can be supplied by a remote peer when RxRPC/AFS-style services are reachable. * Availability impact realistic: +1 Reprocessing partially decrypted RESPONSE packets can cause authentication failure, connection disruption, or protocol-level DoS. * Common networking / protocol path concern: +1 This is in network protocol connection-event handling, although RxRPC itself is not as broadly exposed as TCP/UDP core. Subtracting signals: * Hard triggering condition: -1 Requires a temporary processing failure such as `ENOMEM` or `EAGAIN` after partial decryption. Paranoid additions: * Confidentiality/integrity concern plausible: +1 The bug is in secure RxRPC crypto state handling. Re-decryption can corrupt protocol payload or authentication state, which may have limited C/I consequences depending on how the protocol state is used. * Crypto/protocol state corruption concern: +1 Even without kernel memory corruption, replaying crypto processing on an already modified skb can break authentication semantics and deserves manual validation. No signals apply for UAF, OOB write, arbitrary write, direct privilege escalation, or page-cache/shared-page corruption. ## 3. Reachability analysis The issue is reachable only on systems using RxRPC, such as AFS-related deployments or other RxRPC users. A remote peer can send CHALLENGE or RESPONSE traffic, but reliable triggering also requires temporary processing failures at the right point. Namespaces and containers are not central. The path is not a generic IP stack path, but it is network-facing when RxRPC services are active. ## 4. Severity interpretation This is an Actionable Moderate network protocol crypto-state issue. It is not an Important memory-corruption bug based on the patch. Realistic impact is authentication disruption or connection DoS. Theoretical C/I impact is limited to protocol-state correctness and should be checked, but there is no evidence of kernel memory corruption, data disclosure primitive, or privilege escalation. ## 5. One-sentence report phrase RxRPC could requeue and reprocess a partially decrypted RESPONSE packet after a temporary error, corrupting secure protocol state and allowing remote connection disruption or DoS on reachable RxRPC services. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: the bug is network-reachable in RxRPC deployments and affects crypto/protocol state handling, even though it does not show kernel memory corruption or privilege escalation. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: rxrpc: Fix re-decryption of RESPONSE packets Commit: d61482be4aae1835b78875761206241835a7510e Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d61482be4aae1835b78875761206241835a7510e Commit description: If a RESPONSE packet gets a temporary failure during processing, it may end up in a partially decrypted state - and then get requeued for a retry. Fix this by just discarding the packet; we will send another CHALLENGE packet and thereby elicit a further response. Similarly, discard an incoming CHALLENGE packet if we get an error whilst generating a RESPONSE; the server will send another CHALLENGE. Fixes: 17926a7 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Closes: https://sashiko.dev/#/patchset/20260422161438.2593376-4-dhowells@redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260423200909.3049438-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman Changed files: include/trace/events/rxrpc.h net/rxrpc/conn_event.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=d61482be4aae1835b78875761206241835a7510e ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-45988 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45988 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:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS score: 7 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: 3 Paranoid ActionableScore: 5 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 7.0 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 alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).