NULL pointer dereference in GNU Patch
CVE-2026-56288
GNU patch is vulnerable to a NULL pointer dereference when processing a specially crafted unified-diff patch file. Improper handling of consecutive end-of-file newline markers can corrupt internal hunk (single block of changes in diff) data structures, causing the application to pass a NULL pointer to fwrite() during patch processing. An attacker can trigger this condition with a malicious patch file, causing the utility to crash and resulting in a denial of service. This issue has been fixed in the commit e6d6a4e021660679d7fc9150f981d4920f722313
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.001 (1.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.001
Affected products
- GNU Patch — versions 0
Weakness classification (CWE)
References
- cert.pl/en/posts/2026/07/CVE-2026-56288 (Third Party Advisory, third-party-advisory)
- cgit.git.savannah.gnu.org/cgit/patch.git/ (Product, product, Patch)
- cgit.git.savannah.gnu.org/cgit/patch.git/commit/ (Patch, patch)
Frequently asked questions
- What is CVE-2026-56288?
- CVE-2026-56288 is a medium-severity vulnerability in GNU Patch, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2026-07-09.
- How severe is CVE-2026-56288?
- Medium severity. CVSS v3 base score is 5.5 out of 10.