VulnerabilityPublished 25 Sep 2026Updated 19 Oct 2026

CVE-2026-98123: Linux kernel · sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in ba54cad229977f4fae6355dbdaf117088414fdd0 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.09% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in ba54cad229977f4fae6355dbdaf117088414fdd0, abf59d7f6fff23227256e8199aca5ade45758f8b, 4548d843e7b29f6d150d8caae4e64015fa226b0c +5

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 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 to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ba54cad229977f4fae6355dbdaf117088414fdd0	Fixed in ba54cad229977f4fae6355dbdaf117088414fdd0
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < abf59d7f6fff23227256e8199aca5ade45758f8b	Fixed in abf59d7f6fff23227256e8199aca5ade45758f8b
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4548d843e7b29f6d150d8caae4e64015fa226b0c	Fixed in 4548d843e7b29f6d150d8caae4e64015fa226b0c
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7d8e7ab6a0665888beee91f7ad77ac805963c4fd	Fixed in 7d8e7ab6a0665888beee91f7ad77ac805963c4fd
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7ba84e2971d208a2d6413a334ec28a8a32cdce0f	Fixed in 7ba84e2971d208a2d6413a334ec28a8a32cdce0f
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 5fbc6a778d5fce7628821236972596acb18e1065	Fixed in 5fbc6a778d5fce7628821236972596acb18e1065

AI-suggested

The vulnerability has been fixed in Linux kernel versions after 2.6.12 as indicated by multiple fixed commits. Users and administrators should apply these kernel updates to remediate the issue. No additional mitigations are required as the fix addresses both the infinite loop and out-of-bounds read conditions.

Description

A vulnerability in the Linux kernel SCTP implementation allows a remote attacker to cause a soft lockup (denial of service) by sending a crafted ASCONF-ACK parameter with an odd length that desynchronizes parameter iteration. This leads to an infinite loop in softirq context. Additionally, an out-of-bounds read can occur due to insufficient length checks on error parameters. The issue affects Linux kernel version 2.6.12 and has been fixed in subsequent commits.

Impact

A remote attacker can trigger a denial of service by sending a specially crafted ASCONF-ACK chunk to an ADD-IP enabled SCTP association, causing the kernel to enter a soft lockup state. The vulnerability does not allow code execution or data corruption but results in a pure remote denial of service. Additionally, an out-of-bounds read could potentially lead to information disclosure or kernel instability.

Summary

The Linux kernel SCTP subsystem had a flaw in handling ASCONF-ACK parameters where the verifier and consumer iterated parameters differently due to padding discrepancies. An odd-length parameter could cause the consumer to misinterpret data, leading to a soft lockup via an infinite loop in softirq context, resulting in a remote denial of service. Furthermore, the SCTP_PARAM_ERR_CAUSE parameters lacked proper length validation, causing an out-of-bounds read. The fix involved rejecting short SCTP_PARAM_ERR_CAUSE parameters and aligning the consumer's iteration padding with the verifier's to maintain synchronization. This vulnerability was discovered by Tencent Yunding Lab's ZeroHive.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 12:41 UTC

Technical details

References

Community reviews

Related threats