From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80904][MODERATE REGULAR] net/tls: Fail tls_sw_splice_read() after a failed async decrypt [ Upstream Date: Fri, 04 Sep 2026 18:27:39 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80904 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: a808aadff634c7a408b2ab84d5919e9a741fdb5b List-Id: CVE: CVE-2026-80904 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: net/tls: Fail tls_sw_splice_read() after a failed async decrypt [ Upstream Commit: a808aadff634c7a408b2ab84d5919e9a741fdb5b Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a808aadff634c7a408b2ab84d5919e9a741fdb5b Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80904 Analysis date: Fri, 04 Sep 2026 18:27:39 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline, manual review recommended / Actionable Moderate watchlist Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80904 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80904 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-2026-80904 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80904 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N';CWE-354;CWE-345;CWE-755;Other CVSS 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N';BEST CVSS score: '5.9';DESCR 'A TLS software receive path integrity handling flaw allows tls_sw_splice_read to continue delivering data after an asynchronous decrypt authentication error has broken the connection. A remote peer or a network attacker able to inject invalid TLS records can trigger the error condition, but practical exploitation depends on kTLS software RX, async decrypt behavior, and an application using splice on the TLS socket. For the CVSS the PR:N is used because no local privileges on the target are required beyond network reachability to the affected TLS endpoint. The issue is network reachable but deployment dependent. Impact is mainly integrity related because data may be consumed through splice after recvmsg and read_sock would refuse the same broken connection. There is no evidence of memory corruption, kernel privilege escalation, or direct confidentiality loss from the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended / Actionable Moderate watchlist (with actual score 4) YES REMOTE SIMPLEFIX SKB TEST YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline, manual review recommended / Actionable Moderate watchlist**:: 2. Signal breakdown * Remote reachable / network-triggerable: +2. A remote peer or MITM can create the failed TLS authentication condition by sending invalid TLS records, assuming the endpoint uses the affected kTLS RX path. * Integrity impact plausible: +1. The splice read path can continue delivering records after the connection should be considered broken due to authentication failure. * Common networking receive path, paranoid only: +1. This is in net/tls socket receive handling, but the conservative score does not count it fully because kTLS software RX plus splice plus async decrypt is deployment dependent. * Rare AND difficult-to-reach subsystem/configuration: -1 conservative only. Practical triggering requires kTLS software RX, async decrypt behavior, and an application using splice on the TLS socket. * No memory corruption signal. The patch shows a missing error check, not UAF, OOB write, double free, refcount takeover, or object lifetime corruption. * No LPE signal. There is no supported path to privilege escalation from the patch context. 3. Reachability analysis The bug can be influenced by a remote TLS peer or network attacker able to cause an authentication failure on a kTLS software receive connection. No local privileges on the target are required for the network-side trigger, so PR:N is reasonable for CVSS-style reasoning. However, the vulnerable read behavior only matters when the local application uses tls_sw_splice_read rather than recvmsg or read_sock, and when async decrypt error state is present. This is not a generic TCP packet path for all TLS applications. 4. Severity interpretation This behaves more like an integrity-focused actionable Moderate than an Important-class kernel vulnerability. The realistic impact is that splice can consume data on a connection that other TLS read paths correctly refuse after authentication failure. Theoretical severity is bounded because there is no evidence of memory corruption, kernel crash, data disclosure, arbitrary write, or privilege escalation. Manual review is still justified because the issue is network-influenced and touches TLS authentication semantics. 5. One-sentence report phrase A kTLS software RX logic flaw lets tls_sw_splice_read continue delivering records after an async decrypt authentication failure, making this a network-influenced integrity issue requiring kTLS RX, async decrypt behavior, and splice usage. 6. Manual review recommendation MANUAL CHECK REQUIRED. Network-influenced TLS authentication handling bugs should not be auto-closed even without memory corruption, because application impact depends on how splice output is trusted. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: net/tls: Fail tls_sw_splice_read() after a failed async decrypt [ Upstream Commit: a808aadff634c7a408b2ab84d5919e9a741fdb5b Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a808aadff634c7a408b2ab84d5919e9a741fdb5b Changed files: net/tls/tls_sw.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=a808aadff634c7a408b2ab84d5919e9a741fdb5b ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80904 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80904 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:L/A:N The Best / paranoid CVSS vector: AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N The Best / paranoid CVSS score: 5.9 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: 4 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 alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).