CVE-2026-1757 Red Hat CVE debrief

Who should care

System administrators and users of the xmllint utility, especially in environments where libxml2 is used for parsing XML, should also include affected operators, platform teams, vulnerability management teams, and security teams to assess and mitigate potential impacts. These groups need to evaluate xmllint usage within their environments, apply patches or updates when available, monitor system memory usage for xmllint processes, and consider compensating controls such as limiting xmllint access. They should review and adjust xmllint usage in scripts and applications to prevent potential denial-of-service conditions.

Technical summary

The xmllint utility in libxml2 has a flaw in its interactive shell where memory allocated for user input is not properly released under certain conditions. Specifically, when a user submits input consisting only of whitespace, the program skips command execution but fails to free the allocated buffer. Repeatedly taking this action causes memory to continuously accumulate, potentially exhausting system memory and terminating the xmllint process. This results in a denial-of-service condition on the local system. The vulnerability has a CVSS score of 6.2 and is considered medium severity.

Defensive priority

Medium priority, as it requires specific conditions to be exploited and has a CVSS score of 6.2.

Recommended defensive actions

• Inventory and assess systems for xmllint utility usage.
• Apply vendor patches or updates when available.
• Monitor system memory usage for xmllint processes.
• Consider compensating controls such as limiting xmllint access.
• Review and adjust xmllint usage in scripts and applications.

Evidence notes

The CVE record and NVD entry provide details about the vulnerability. However, the vendor and product information is not clearly stated, with the vendor listed as 'Unknown Vendor'. Red Hat has references to this CVE in their errata and security pages.

Official resources