CVE-2026-19499

Buffer overflow in strfmon and strfmon_l right-justification padding

HIGH
7.7
CVSS Score
Published: September 14, 2026 at 05:11 PM UTC
Updated: September 18, 2026 at 06:29 PM UTC
1 product affected across 1 vendorGlibc

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Severity
HIGH7.7
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Calling strfmon and strfmon_l in the GNU C Library version 2.38 to 2.44 can write past the end of the caller-supplied output buffer when a conversion uses right-justified width padding. Exploitation requires an application code path that calls strfmon or strfmon_l with right-justified width padding into a destination buffer that is large enough for the padding to succeed but too small for the internal memmove call. The field width or format may be attacker-influenced or a fixed susceptible pattern in the caller. At the time of publication, no network-facing application impact is known.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.38 ≤ v ≤ 2.442.38

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.7HIGHglibc
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-122

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