Bug 2516821 (CVE-2026-74399)

Summary: CVE-2026-74399 kernel: evm: terminate and bound the evm_xattrs read buffer
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's Extended Verification Module (EVM). The `evm_read_xattrs()` function, when processing extended attributes, fails to properly initialize a buffer. This can lead to an out-of-bounds read when no extended attributes are configured, potentially allowing an attacker to cause a denial of service (DoS) or disclose sensitive information.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-08-15 06:35:15 UTC
In the Linux kernel, the following vulnerability has been resolved:

evm: terminate and bound the evm_xattrs read buffer

evm_read_xattrs() allocates size + 1 bytes, fills them from the list of
enabled xattrs, and then passes strlen(temp) to
simple_read_from_buffer(). When no configured xattrs are enabled, the
fill loop stores nothing and temp[0] remains uninitialized, so strlen()
reads beyond initialized memory.

Explicitly terminate the buffer after allocation, use snprintf() for
each formatted line, and pass the accumulated length, without risk of
truncation, to simple_read_from_buffer().