Linux KernelOperating system · Linux
CVE-2026-52931
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: batman-adv: tp_meter: avoid use of uninit sender vars batadv_tp_recv_ack() and batadv_tp_stop() are only valid for tp_vars in the BATADV_TP_SENDER role. When called with a BATADV_TP_RECEIVER role, it proceeds to read sender-only members that were never initialized, leading to undefined behavior. This can be triggered when a node that is currently acting as a receiver in an ongoing tp_meter session receives a malicious ACK packet. Guard against this by checking tp_vars->role immediately after the lookup and bailing out if it is not BATADV_TP_SENDER, before any of those members are accessed.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceIn the Linux kernel batman-adv module, tp_meter functions batadv_tp_recv_ack() and batadv_tp_stop() lack validation of the tp_vars role before accessing sender-only members. When these functions are called with a BATADV_TP_RECEIVER role (e.g., via malicious ACK packet to a receiver node), they read uninitialized sender-specific memory, causing undefined behavior.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 4.8, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.142>= 6.7, < 6.12.92>= 6.13, < 6.18.34>= 6.19, < 7.0.11= 7.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify batman-adv kernel module is loadedRun `lsmod | grep batman_adv` or check if directory /sys/module/batman_adv/ existsAffected if The module is not loaded means the attack surface does not exist
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Determine the running kernel versionRun `uname -r` and compare the version number against the affected ranges: >= 4.8, < 5.10.258; >= 5.11, < 5.15.209; >= 5.16, < 6.1.175; >= 6.2, < 6.6.142; >= 6.7, < 6.12.92; >= 6.13, < 6.18.34; >= 6.19, < 7.0.11; = 7.1Affected if The kernel version falls within any of the affected version ranges listed
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Check if batman-adv tp_meter functionality is in useExamine debugfs or batctl output for active throughput meter sessions: `batctl tp` or check /sys/kernel/debug/batman_adv/ for tp_meter related entriesAffected if Active tp_meter sessions exist, indicating the vulnerable code path could be triggered
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Verify the tp_vars role validation is absent in source codeIf kernel source is available, inspect net/batman-adv/tp_meter.c for batadv_tp_recv_ack() and batadv_tp_stop() functions - look for role validation before accessing sender-only members (e.g., last_round, supp_rate, etc.)Affected if No role validation (BATADV_TP_SENDER check) is performed before accessing sender-specific tp_vars members
You are affected if the batman-adv module is loaded, your kernel version is within the listed affected ranges, and tp_meter functionality is actively being used or the unpatched code lacks role validation.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.10.2585.15.2096.1.175
Apply the kernel patch that adds immediate role validation after tp_vars lookup, bailing out if the role is not BATADV_TP_SENDER before any sender-only members are accessed.
6.6.142 or later (or 6.1.175, 5.15.209, 5.10.258 depending on your branch)
- Identify the current running kernel version using 'uname -r'
- Determine which kernel branch your current version belongs to (e.g., if running 5.15.x, target 5.15.209 or later)
- Upgrade the Linux kernel to a version that includes the fix: 5.10.258 or later for 5.10.x, 5.15.209 or later for 5.15.x, 6.1.175 or later for 6.1.x, or 6.6.142 or later for 6.2.x through 6.6.x
- For distribution kernels (Debian, Ubuntu, Red Hat, etc.), apply the vendor's kernel security update which incorporates this fix
- Reboot the system to load the fixed kernel
- Verify the fix is applied by checking the kernel version matches or exceeds the fixed versions above
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-52931 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-52931 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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