CVE-2026-124077 (CVSS 4.3)

Description

The GitIdentifiers class in Apache Commons Codec did not reject NUL bytes in tree entry names. Because Git uses a NUL byte to mark the end of each entry name in a tree object, a crafted name could make one tree serialize to the same bytes as a different tree. Two different directory trees could then receive the same Git tree identifier or SWHID. The impact is limited: common file systems do not allow NUL bytes in file names, so trees built by walking a file system are not affected. Only applications that build trees from names supplied by other sources, such as entries of archive formats that permit NUL bytes in names (e.g. ZIP) or names passed directly to the API, are exposed. This issue affects Apache Commons Codec: from 1.22.0 before 1.23.0. Users are recommended to upgrade to version 1.23.0, which fixes the issue.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-158 CWE-158

References

Other References

https://github.com/apache/commons-codec/commit/87f6aa2818836998528ff4b0d1ea35545a800ee5.patch https://lists.apache.org/thread.html/zns7tbnkq685prps9d85q7ct6oobvzsm http://www.openwall.com/lists/oss-security/2026/11/09/30

Frequently Asked Questions

What is CVE-2026-124077? +

The GitIdentifiers class in Apache Commons Codec did not reject NUL bytes in tree entry names. Because Git uses a NUL byte to mark the end of each entry name in a tree object, a crafted name could make one tree serialize to the same bytes as a different tree. Two different directory trees could then receive the same Git tree identifier or SWHID. The impact is limited: common file systems do not allow NUL bytes in file names, so trees built by walking a file system are not affected. Only applications that build trees from names supplied by other sources, such as entries of archive formats that permit NUL bytes in names (e.g. ZIP) or names passed directly to the API, are exposed. This issue affects Apache Commons Codec: from 1.22.0 before 1.23.0. Users are recommended to upgrade to version 1.23.0, which fixes the issue. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-124077? +

CVE-2026-124077 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-124077? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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