Unknown

CVE-2026-98123 — sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration

In the Linux kernel, the following vulnerability has been resolved: sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration sctp_verify_asconf() walks ASCONF-ACK parameters with sctp_walk_params(), which advances by SCTP_PAD4(length), while the consumer sctp_get_asconf_response() iterates the same parameters advancing by the raw length, without padding. A single odd-length parameter desynchronises the two walks and makes the consumer interpret attacker-controlled bytes at a misaligned offset. When those bytes yield a length of zero, the while loop over asconf_ack_len makes no progress, spinning forever in softirq context, and the watchdog reports a soft lockup. All reads stay within the received skb, so the lockup is a pure remote denial of service. A remote peer can trigger it with a crafted ASCONF-ACK on an ADD-IP enabled association with an outstanding ASCONF (RFC 5061 section 4.1.2 requires the chunk to be authenticated, but the predefined empty key id 0 allows the peer to compute the same association HMAC from publicly exchanged parameters, so the gate does not help). The SCTP_PARAM_ERR_CAUSE case of sctp_verify_asconf() also performs no length check, letting a parameter without a complete error header reach the consumer, which reads errhdr.cause past the end of the parameter, an out-of-bounds read. Reject SCTP_PARAM_ERR_CAUSE parameters shorter than sizeof(struct sctp_addip_param) + sizeof(struct sctp_errhdr) at the verifier, and advance the consumer iterator with the same padding rule as the verifier to keep the two walks in lockstep. The verifier change guarantees a complete error header in every ERR_CAUSE parameter the consumer can see, so the consumer's asconf_ack_len check is dropped and it returns err_param->cause directly. The consumer padding fix is still required because odd lengths remain valid for SCTP_PARAM_ERR_CAUSE per RFC 5061. The issue was found by ZeroHive, a vulnerability hunting agent at Tencent Yunding Lab.

Published Sep 25, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.18%

ahead of 7% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < ba54cad229977f4fae6355dbdaf117088414fdd0≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7d8e7ab6a0665888beee91f7ad77ac805963c4fd≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 5fbc6a778d5fce7628821236972596acb18e1065≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 4548d843e7b29f6d150d8caae4e64015fa226b0c≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < abf59d7f6fff23227256e8199aca5ade45758f8b≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 3be02999ab9131a4b96eb1eda4ca48b1cea80f03≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 7ba84e2971d208a2d6413a334ec28a8a32cdce0f≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 2cb0b0b1ed69430bf73740377ea0a1c44c50db63 and 1 more version 2.6.12	Vulnerable	CVE Program (cve.org) e CISA ADP

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Undergoing Analysis
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 25, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/abf59d7f6fff23227256e8199aca5ade45758f8b
NIST National Vulnerability Database
git.kernel.org/stable/c/3be02999ab9131a4b96eb1eda4ca48b1cea80f03
NIST National Vulnerability Database
git.kernel.org/stable/c/4548d843e7b29f6d150d8caae4e64015fa226b0c
NIST National Vulnerability Database
git.kernel.org/stable/c/ba54cad229977f4fae6355dbdaf117088414fdd0
NIST National Vulnerability Database
git.kernel.org/stable/c/5fbc6a778d5fce7628821236972596acb18e1065
NIST National Vulnerability Database
git.kernel.org/stable/c/7ba84e2971d208a2d6413a334ec28a8a32cdce0f
NIST National Vulnerability Database
git.kernel.org/stable/c/2cb0b0b1ed69430bf73740377ea0a1c44c50db63
NIST National Vulnerability Database
git.kernel.org/stable/c/7d8e7ab6a0665888beee91f7ad77ac805963c4fd
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 1d
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 1d
Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 2d
Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 2d
Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 2d
Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-98123 is "sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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