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Linux Kernel EUVDEUVD-2026-59255

| CVE-2026-72356 HIGH
2026-08-15 Linux GHSA-fvfj-x9c7-958j
7.5
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.9 MEDIUM

AC raised to H because exploitation requires attacker control of a server the victim actively mounts; PR:N since the attacker operates server-side; A:H for full mount stall.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
4.7 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

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

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 08:45 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
7.5 (HIGH)
Patch available
Aug 15, 2026 - 07:20 EUVD
CVE Published
Aug 15, 2026 - 05:55 cve.org
UNKNOWN (no severity yet)
CVE Published
Aug 15, 2026 - 05:55 cve.org
HIGH 7.5

DescriptionCVE.org

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

cifs: Fix missing credit release on failure in cifs_issue_read()

Fix missing release of credits in the failure path in cifs_issue_read() lest retrying the subreq just overwrites the credits value.

AnalysisAI

Credit resource leak in the Linux kernel CIFS client function cifs_issue_read() enables a server-side actor to exhaust the SMB flow-control credit pool on a connected Linux host, producing a denial of service for all I/O on the affected CIFS mount. Linux kernel versions from commit 69c3c023af25edb5433a2db824d3e7cc328f0183 onward are affected until stable-tree patches landing in 6.12.97, 6.18.40, 7.1.5, and 7.2-rc2. No public exploit identified at time of analysis; EPSS of 0.21% (11th percentile) confirms very low real-world exploitation probability and no CISA KEV listing exists.

Technical ContextAI

The Linux kernel CIFS client implements the SMB/CIFS protocol for mounting remote Windows and Samba file shares. SMB uses a credits mechanism as a flow-control quota: the server grants the client a finite number of outstanding request slots. In the async read path, cifs_issue_read() acquires credits before issuing a read operation. The defect is in the failure path: when cifs_issue_read() returns an error, it fails to release the acquired credits back to the pool. When the caller retries the subrequest, it simply overwrites the stale credits value rather than adding to the pool, causing a permanent per-failure credit leak. Repeated triggering of this failure path drains the credit pool entirely, after which the CIFS client can issue no further requests to the server and all I/O on that mount stalls. The CWE is not formally assigned in the input data, but the root cause class is a resource management error (analogous to CWE-772: Missing Release of Resource after Effective Lifetime). Affected product is identified via CPE cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*.

RemediationAI

Upgrade to a patched Linux kernel version: 6.12.97, 6.18.40, 7.1.5, or 7.2-rc2, incorporating the fixes committed at https://git.kernel.org/stable/c/b9ee1f0347bf56d019ca28ddff090234bb45b05c, https://git.kernel.org/stable/c/86652704a7fd41a5a8459027e08640bbd1952826, https://git.kernel.org/stable/c/3a303f985c6bec8787c2ad4a16b39c14c5bcd765, and https://git.kernel.org/stable/c/c16b8c4cfb4fe2244cc33e469a93c1ab8684146b. Linux distribution vendors (Debian, Ubuntu, Red Hat, SUSE) are expected to backport these commits to their supported kernel packages; check distribution security advisories for package-specific fix versions. If immediate patching is not possible, unmounting CIFS shares from untrusted or externally reachable servers eliminates the attack surface at the cost of losing access to those shares. Restricting SMB traffic (TCP 445) at the perimeter to only trusted server IPs limits the attacker-controlled-server vector without disrupting internal file share access. No generic workaround restores CIFS functionality while fully mitigating the credit leak without a kernel patch.

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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EUVD-2026-59255 vulnerability details – vuln.today

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