microtar Stack Buffer Overflow in mtar_write_file_header() and mtar_write_dir_header()

published 2026-08-05 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-53352

cvss: 9.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits: 0; none known

microtar's mtar_write_file_header and mtar_write_dir_header functions (src/microtar.c) copy a caller-supplied entry name into the 100-byte field of a stack-allocated mtar_header_t via strcpy(h.name, name), with no check that strlen(name) is less than 100 before the copy.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-71267 updated 2026-08-06 cvss 8.8

microtar: microtar: Stack buffer overflow via overly long filenames

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 3 mo ago (2026-08-05)

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

rxi microtar

Classification

Weakness

CWE-121 Stack-based Buffer Overflow

References

github.com /rxi/microtar
third-party-advisory
github.com /rxi/microtar/blob/master/src/microtar.c
third-party-advisory

Sources

CVE List CVE-2026-71267
NVD CVE-2026-71267

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary