VulnerabilityPublished 23 Oct 2026

CVE-2026-99031: Linux kernel · net: bridge: avoid recursive multicast port cleanup

Source GCVE Database

Authoritative record:CVE-2026-99031· Medium

Not known to be exploited · fixed in d109141ba14652146089ef78b32d5e4d5285ebad : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d109141ba14652146089ef78b32d5e4d5285ebad, 5158353121bae4f552cb677ce8c5c3ef52f93a0d, 7931fb9181421953f3133b408b0f2e2b8dd68b61 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-c83g-q254-qmxr

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 8266a0491e92d39dc9af739e8380a0daa9b8836b, < d109141ba14652146089ef78b32d5e4d5285ebad	Fixed in d109141ba14652146089ef78b32d5e4d5285ebad
LinuxLinux	Affected ≥ 8266a0491e92d39dc9af739e8380a0daa9b8836b, < 5158353121bae4f552cb677ce8c5c3ef52f93a0d	Fixed in 5158353121bae4f552cb677ce8c5c3ef52f93a0d
LinuxLinux	Affected ≥ 8266a0491e92d39dc9af739e8380a0daa9b8836b, < 7931fb9181421953f3133b408b0f2e2b8dd68b61	Fixed in 7931fb9181421953f3133b408b0f2e2b8dd68b61
LinuxLinux	Affected ≥ 8266a0491e92d39dc9af739e8380a0daa9b8836b, < 695a5a4c69c922d9296b2d7ad5f1ce8c6858fc64	Fixed in 695a5a4c69c922d9296b2d7ad5f1ce8c6858fc64
LinuxLinux	Affected ≥ 8266a0491e92d39dc9af739e8380a0daa9b8836b, < 2fb87c6025f90191516bee3ce14b42eb3e1cfed7	Fixed in 2fb87c6025f90191516bee3ce14b42eb3e1cfed7
LinuxLinux	Affected =5.10	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: net: bridge: avoid recursive multicast port cleanup br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL port groups by calling br_multicast_del_pg(). For S,G entries, that deletion calls back into br_multicast_sg_del_exclude_ports(), so a large number of STAR_EXCL ports consumes one kernel stack frame per port and can hit the stack guard page. Keep the complete port-group deletion path for cleanup, but suppress the S,G exclude-port cleanup while that helper is already walking the same entry. Normal deletion callers retain the existing behavior.

References

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