VulnerabilityPublished 28 Oct 2026

CVE-2026-99128: Linux kernel · sctp: validate chunk length in the inqueue parser

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 40507f59f230dcf60ae13cb48d34f8c6e9f40659 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in 40507f59f230dcf60ae13cb48d34f8c6e9f40659, 9ac57e4c62e93c287b36080e5da3645690549990, 6cfc1b90cb86f4aabc69fb8e30128e07e2cdfa3a

Exploitation evidence

Disclosed: evidence found.
CVE published 28 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.

What to do

Upgrade Linux kernel to 40507f59f230dcf60ae13cb48d34f8c6e9f40659, 9ac57e4c62e93c287b36080e5da3645690549990 or 6cfc1b90cb86f4aabc69fb8e30128e07e2cdfa3a.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ bbd0d59809f923ea2b540cbd781b32110e249f6e, < 40507f59f230dcf60ae13cb48d34f8c6e9f40659	Fixed in 40507f59f230dcf60ae13cb48d34f8c6e9f40659
LinuxLinux	Affected ≥ bbd0d59809f923ea2b540cbd781b32110e249f6e, < 9ac57e4c62e93c287b36080e5da3645690549990	Fixed in 9ac57e4c62e93c287b36080e5da3645690549990
LinuxLinux	Affected ≥ bbd0d59809f923ea2b540cbd781b32110e249f6e, < 6cfc1b90cb86f4aabc69fb8e30128e07e2cdfa3a	Fixed in 6cfc1b90cb86f4aabc69fb8e30128e07e2cdfa3a
LinuxLinux	Affected =2.6.24	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: validate chunk length in the inqueue parser SCTP chunks always include a four-byte generic header, but sctp_inq_pop() currently accepts shorter declared lengths. A zero-length chunk leaves chunk_end at the current header. When ASCONF is covered by the association's SCTP-AUTH policy, sctp_assoc_bh_rcv() can continue before the state machine performs its normal chunk-length check. sctp_inq_pop() then returns the same malformed chunk repeatedly and the receive softirq can lock up. A remote SCTP peer can trigger this after establishing an association on a kernel built with CONFIG_IP_SCTP and configured with net.sctp.addip_enable=1 and net.sctp.auth_enable=1. The reproducer did not require application credentials, a shared SCTP AUTH key, or net.sctp.addip_noauth_enable=1. On commit f967455fb2a5 ("seg6: reset IP6CB after IPv6 decapsulation"), one zero-length ASCONF caused repeated watchdog soft-lockup reports in a two-vCPU KVM guest. All 3 pre-trigger health probes succeeded, while 36 of 37 post-trigger probes failed. With this change, all 37 post-trigger probes succeeded and no equivalent soft-lockup signature appeared. Reject chunks shorter than the generic SCTP header at the shared inqueue parser boundary. Mark the packet for discard before either caller can continue processing it, while preserving the four-byte generic minimum. Declared-length 1 through 4 controls and kernel-generated ASCONF traffic remained healthy. The patched sctp_hello selftest passed for IPv4 and IPv6. The complete private reproducer and validation evidence are available directly to maintainers on request.

References

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