Bug 2461763 (CVE-2026-31677)

Summary:	CVE-2026-31677 kernel: crypto: af_alg - limit RX SG extraction by receive buffer budget
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	pasik, rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's `af_alg` (Algorithm Interface) component. This vulnerability allows a local attacker to cause a denial of service (DoS) by sending specially crafted requests. The `af_alg_get_rsgl()` function fails to properly limit the extraction of receive scatterlist (RX SG) data based on the available receive buffer, leading to the rejection of `recvmsg` calls and preventing further data processing.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-25 09:01:55 UTC

In the Linux kernel, the following vulnerability has been resolved:

crypto: af_alg - limit RX SG extraction by receive buffer budget

Make af_alg_get_rsgl() limit each RX scatterlist extraction to the
remaining receive buffer budget.

af_alg_get_rsgl() currently uses af_alg_readable() only as a gate
before extracting data into the RX scatterlist. Limit each extraction
to the remaining af_alg_rcvbuf(sk) budget so that receive-side
accounting matches the amount of data attached to the request.

If skcipher cannot obtain enough RX space for at least one chunk while
more data remains to be processed, reject the recvmsg call instead of
rounding the request length down to zero.

Comment 1 Alexander B 2026-04-27 10:56:44 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042544-CVE-2026-31677-1a29@gregkh/T

Comment 3 errata-xmlrpc 2026-05-19 13:08:12 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:19074 https://access.redhat.com/errata/RHSA-2026:19074

Comment 4 errata-xmlrpc 2026-05-19 18:03:20 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:19225 https://access.redhat.com/errata/RHSA-2026:19225