CVE-2026-64095: In the Linux kernel, the following vulnerability has been resolved: batman-adv: bla: avoid double decrement of bla.num_requests The bla.num_requests is increased when no request_
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: bla: avoid double decrement of bla.num_requests
The bla.num_requests is increased when no request_sent was in progress. And
it is decremented in various places (announcement was received, backbone is
purged, periodic work). But the check if the request_sent is actually set
to a specific state and the atomic_dec/_inc are not safe because they are
not atomic (TOCTOU) and multiple such code portions can run concurrently.
At the same time, it is necessary to modify request_sent (state) and
bla.num_requests atomically. Otherwise batadv_bla_send_request() might set
request_sent to 1 and is interrupted. batadv_handle_announce() can then
set request_sent back to 0 and decrement num_requests before
batadv_bla_send_request() incremented it.
The two operations must therefore be locked. And since state (request_sent)
and wait_periods are only accessed inside this lock, they can be converted
to simpler datatypes. And to avoid that the bla.num_requests is touched by
a parallel running context with a valid backbone_gw reference after
batadv_bla_purge_backbone_gw() ran, a third state "stopped" is required to
correctly signal that a backbone_gw is in the state of being cleaned up.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-64095
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-640950.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 19% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-64095 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
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