CVE-2018-5735 Backport of the fix for CVE-2017-3137 leads to assertion failure in validator.c:1858

What is CVE-2018-5735?

CVE-2018-5735 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 30 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The Debian backport of the fix for CVE-2017-3137 leads to assertion failure in validator.c:1858; Affects Debian versions 9.9.5.dfsg-9+deb8u15; 9.9.5.dfsg-9+deb8u18; 9.10.3.dfsg.P4-12.3+deb9u5; 9.11.5.P4+dfsg-5.1 No ISC releases are affected. Other packages from other distributions who did similar backports for the fix for 2017-3137 may also be affected.

Weakness: CWE-617

Which versions are affected by CVE-2018-5735?

It affects 1 product.

Products include Debian Debian Linux.

How do I fix CVE-2018-5735?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-5735 being exploited?

There is no known exploitation of CVE-2018-5735 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

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• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2018-5735, DLA-1285-1, GHSA-qp2w-qqh3-4x36.