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Linux Kernel EUVDEUVD-2026-32336

| CVE-2026-45870 MEDIUM
Memory Leak (CWE-401)
2026-05-27 416baaa9-dc9f-4396-8d5f-8c081fb06d67 GHSA-cc2x-2xg8-9rpf
5.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.5 MEDIUM

Local-only trigger requiring low-privilege NFS/Kerberos auth access; pure memory leak with no confidentiality or integrity impact, only availability via gradual exhaustion.

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

Primary rating from NVD.

CVSS VectorNVD

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

Lifecycle Timeline

5
Analysis Generated
Jun 25, 2026 - 21:14 vuln.today
CVSS changed
Jun 25, 2026 - 21:07 NVD
5.5 (MEDIUM)
Patch available
May 27, 2026 - 19:46 EUVD
CVE Published
May 27, 2026 - 14:17 nvd
UNKNOWN (no severity yet)
CVE Published
May 27, 2026 - 14:17 nvd
MEDIUM 5.5

DescriptionNVD

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

SUNRPC: auth_gss: fix memory leaks in XDR decoding error paths

The gssx_dec_ctx(), gssx_dec_status(), and gssx_dec_name() functions allocate memory via gssx_dec_buffer(), which calls kmemdup(). When a subsequent decode operation fails, these functions return immediately without freeing previously allocated buffers, causing memory leaks.

The leak in gssx_dec_ctx() is particularly relevant because the caller (gssp_accept_sec_context_upcall) initializes several buffer length fields to non-zero values, resulting in memory allocation:

struct gssx_ctx rctxh = { .exported_context_token.len = GSSX_max_output_handle_sz, .mech.len = GSS_OID_MAX_LEN, .src_name.display_name.len = GSSX_max_princ_sz, .targ_name.display_name.len = GSSX_max_princ_sz };

If, for example, gssx_dec_name() succeeds for src_name but fails for targ_name, the memory allocated for exported_context_token, mech, and src_name.display_name remains unreferenced and cannot be reclaimed.

Add error handling with goto-based cleanup to free any previously allocated buffers before returning an error.

AnalysisAI

Memory leaks in the Linux kernel's SUNRPC auth_gss subsystem allow a local low-privilege attacker to gradually exhaust kernel heap memory on systems using NFS with Kerberos (RPCSEC_GSS) authentication. The gssx_dec_ctx(), gssx_dec_status(), and gssx_dec_name() XDR decoding functions fail to release previously allocated kernel buffers when a partial decode sequence errors out mid-function, leaving unreferenced kmemdup() allocations on the heap. No public exploit exists and EPSS is 0.02%, but no public exploit identified at time of analysis; repeated triggering of the vulnerable paths could degrade availability on RPCSEC_GSS-enabled servers.

Technical ContextAI

The flaw resides in the Linux kernel SUNRPC subsystem, specifically the GSS-API (Generic Security Services) authentication layer used by RPCSEC_GSS to secure NFS and other RPC traffic with Kerberos or similar mechanisms. The root cause is CWE-401 (Missing Release of Memory after Effective Lifetime): gssx_dec_ctx(), gssx_dec_status(), and gssx_dec_name() each call gssx_dec_buffer(), which uses kmemdup() to allocate kernel heap memory for fields such as exported_context_token, mech OID, and principal display names (src_name, targ_name). When any subsequent field decode in the same call fails, the function returns the error immediately without freeing buffers successfully allocated for prior fields. The caller gssp_accept_sec_context_upcall pre-initializes struct gssx_ctx with non-zero length values for all four buffer fields, guaranteeing actual allocations occur before any potential failure point. The fix applies goto-based cleanup labels to free all previously allocated buffers on any error exit path. CPE cpe:2.3:o:linux:linux_kernel applies across all affected stable branches.

RemediationAI

Upgrade to a vendor-released patched kernel version: 5.10.252 or later for the 5.10.x stable branch, 5.15.202+ for 5.15.x, 6.1.165+ for 6.1.x, 6.6.128+ for 6.6.x, 6.12.75+ for 6.12.x, 6.18.14+ for 6.18.x, 6.19.4+ for 6.19.x, or any 7.0+ release. Representative patch commit: https://git.kernel.org/stable/c/3b56eb90feb8a3709417f5624f3871847d42bcb1. If immediate kernel upgrade is not feasible, a compensating control is to disable NFS mounts using Kerberos (RPCSEC_GSS) or restrict gssproxy access, which prevents the vulnerable XDR decode paths from being exercised - trade-off is loss of Kerberos-secured NFS functionality. Restricting local shell access for untrusted users on NFS/Kerberos servers also reduces exposure. There is no known userspace-only mitigation that addresses the kernel memory leak itself.

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
Image SLES12-SP5-Azure-BYOS Affected
Image SLES12-SP5-Azure-SAP-BYOS Image SLES12-SP5-Azure-SAP-On-Demand Image SLES12-SP5-EC2-SAP-On-Demand Affected
SUSE Linux Enterprise Server 12 SP5-LTSS Fixed
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 Fixed
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected

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EUVD-2026-32336 vulnerability details – vuln.today

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