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CVE-2026-56288 GNU CVE debrief

CVE-2026-56288 is a NULL pointer dereference vulnerability in GNU patch. The vulnerability occurs when processing a specially crafted unified-diff patch file, which can cause the application to pass a NULL pointer to fwrite() during patch processing. This can be triggered by a malicious patch file, leading to a denial of service. The vulnerability has been fixed in the commit e6d6a4e021660679d7fc9150f981d4920f722313. Users of GNU patch should be aware of this vulnerability and take steps to mitigate it, especially those who process patch files from untrusted sources.

Vendor
GNU
Product
patch
CVSS
MEDIUM 4.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-09
Original CVE updated
2026-07-13
Advisory published
2026-07-09
Advisory updated
2026-07-13

Who should care

Users of GNU patch, especially those who process patch files from untrusted sources, should be aware of this vulnerability and take steps to mitigate it. This includes applying the patch from the GNU patch repository, using a trusted source for patch files, and validating patch files before processing them. Security teams and operators responsible for patch management and vulnerability remediation should prioritize this vulnerability.

Technical summary

The vulnerability is caused by improper handling of consecutive end-of-file newline markers in a specially crafted unified-diff patch file. This can corrupt internal hunk data structures, leading to a NULL pointer being passed to fwrite() during patch processing. The vulnerability affects GNU patch and can be triggered by a malicious patch file, leading to a denial of service. The fix involves updating the patch processing logic to handle consecutive end-of-file newline markers correctly.

Defensive priority

Medium

Recommended defensive actions

  • Apply the patch from the GNU patch repository
  • Use a trusted source for patch files
  • Validate patch files before processing them
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-09T11:16:40.713Z and was last modified on 2026-07-13T14:08:47.080Z. The NVD entry is currently Analyzed. This information is based on the NVD entry and the CVE record. The vulnerability affects GNU patch and can be triggered by a malicious patch file, leading to a denial of service. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-56288 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-56288

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-56288 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-56288

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.