VulnerabilityPublished 24 Sep 2026Updated 30 Oct 2026

CVE-2026-93228: Linux kernel · svcrdma: Reject Write/Reply chunks with segcount 0

Source GCVE Database

Authoritative record:CVE-2026-93228· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical · fixed in fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f : patch Linux kernel as a priority.

Data as of 30 Oct 2026, 17:52 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (Linux)	CVSS 3.1	9.1

Patch: Available – fixed in fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f, ac730b8cbaeec6831116e1455d909ecbdcdcbd34, a798714b58041e88716db3bf8fb03ae13eecd54a +3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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-g29j-c673-5ccw

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f	Fixed in fe533ae1bed2ef2b3d54ee7ab410da1874ed3d4f
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < ac730b8cbaeec6831116e1455d909ecbdcdcbd34	Fixed in ac730b8cbaeec6831116e1455d909ecbdcdcbd34
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < a798714b58041e88716db3bf8fb03ae13eecd54a	Fixed in a798714b58041e88716db3bf8fb03ae13eecd54a
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < 9808eb7656666acc7291bae9ab6b987bd16e47e0	Fixed in 9808eb7656666acc7291bae9ab6b987bd16e47e0
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < 45dbdb2637b7fc5f1355b588780d2a7fb0516805	Fixed in 45dbdb2637b7fc5f1355b588780d2a7fb0516805
LinuxLinux	Affected ≥ 78147ca8b4a9b6cf0e597ddd6bf17959e08376c2, < 28c5a3a572f6cf81ac304459cfd515480995d62a	Fixed in 28c5a3a572f6cf81ac304459cfd515480995d62a

AI-suggested

A fix has been implemented in the Linux kernel to reject Write/Reply chunks with segcount zero at the decode boundary, preventing malformed chunks from being processed. Users should update to the patched kernel versions once available. Since this is a kernel vulnerability, applying official kernel updates from the vendor or distribution is the recommended remediation. No additional mitigations are necessary as the patch fully addresses the issue.

Description

CVE-2026-93228 is a critical vulnerability in the Linux kernel's svcrdma module where Write or Reply chunks with a segcount of zero are improperly accepted. This flaw allows malformed chunks that describe no remote buffer to be linked into parsed chunk lists, potentially leading to memory handling issues. The vulnerability has been resolved by rejecting such zero-segcount chunks at the decode boundary, preventing malformed frames from being processed. No legitimate clients are affected as per RFC 8166, and the fix improves defense in depth by ensuring only fully-populated chunks are processed.

Impact

An attacker can send malformed Write or Reply chunks with segcount zero, which previously bypassed validation and could lead to malformed data structures in kernel memory. This could cause memory corruption or denial of service due to improper handling of these chunks. The vulnerability is rated critical with a CVSS score of 9.1, indicating high impact on confidentiality and availability. However, no known exploits are reported in the wild. Legitimate clients are not affected as such chunks have no valid meaning per RFC 8166.

Summary

The Linux kernel svcrdma module previously allowed Write or Reply chunks with a segcount field of zero to pass validation because xdr_check_write_chunk() only rejected segcount values greater than rc_maxpages. This allowed malformed chunks with zero segments to be linked into internal parsed chunk lists, potentially exposing consumers to incomplete or degenerate data structures. The patch enforces rejection of zero-segcount chunks at the decoding stage, preventing them from entering the parsed chunk lists. This change also reorders list insertion to occur after segment arrays are fully populated, ensuring only complete chunks are visible. The vulnerability is addressed as a defense-in-depth measure, with no impact on legitimate clients according to RFC 8166.

References

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