CVE-2026-52919

Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix tp_meter counter underflow during shutdown batadv_tp_sender_shutdown() unconditionally decrements the "sending" atomic counter. If multiple paths (e.g. timeout, user cancel, and normal finish) call this function, the counter can underflow to -1. Since the sender logic treats any non-zero value as "still sending", a negative value causes the sender kthread to loop indefinitely. This leads to a use-after-free when the interface is removed while the zombie thread is still active. Fix this by using atomic_xchg() to ensure the counter only transitions from 1 to 0 once. [sven: added missing change in batadv_tp_send]

CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0012

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/01cefc5923889e29dbb5f281c3d457714ceb9c00 https://git.kernel.org/stable/c/90ae3eae06b7b8ab9f6250b9497c860915b4c17b https://git.kernel.org/stable/c/94f3b133168d1c49895e7cc6afbcf1cc0b354602 https://git.kernel.org/stable/c/abae88fa254f2981d39ac003a7b302528a22af64 https://git.kernel.org/stable/c/aeae11c5dad9cd0d50723890bdd866f8e6db2e7d https://git.kernel.org/stable/c/c1bac194733aabd731aafa6a01350c229e187dba https://git.kernel.org/stable/c/c66d20a3ff095e3f000551d208ec2606616db15c https://git.kernel.org/stable/c/e75e2ab463b5b34df6b98f94d740aff327ce9f6b

Frequently Asked Questions

What is CVE-2026-52919? +

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix tp_meter counter underflow during shutdown batadv_tp_sender_shutdown() unconditionally decrements the "sending" atomic counter. If multiple paths (e.g. timeout, user cancel, and normal finish) call this function, the counter can underflow to -1. Since the sender logic treats any non-zero value as "still sending", a negative value causes the sender kthread to loop indefinitely. This leads to a use-after-free when the interface is removed while the zombie thread is still active. Fix this by using atomic_xchg() to ensure the counter only transitions from 1 to 0 once. [sven: added missing change in batadv_tp_send] It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-52919? +

CVE-2026-52919 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0012, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-52919? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.