2.1

CVE-2026-103923: KaTeX: Existing prototype pollution can bypass trust restrictions

Awaiting analysis
AliasesUBUNTU-CVE-2026-103923DEBIAN-CVE-2026-103923CGA-2jqm-9r6j-ff5q
Published 01-10-2026Last modified 06-10-2026

Vulnerability summary

CVE-2026-103923 is a low (CVSS 2.1) vulnerability in katex. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 22.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 2.1, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
2.1/10
010
Low · v4.0 (CVE.org)
EPSS score
0.30%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 01-10-2026
    PublishedVulnerability first disclosed.
  2. 06-10-2026
    Last modifiedVulnerability information updated.

Description

KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. From 0.11.0 until 0.18.2, KaTeX uses ordinary JavaScript property access for the renderer options object, the trust setting, default and processor setting metadata, and namespace lookup and group restoration, allowing inherited properties to be treated as explicitly supplied values. When Object.prototype is already polluted or an attacker controls the options object's prototype, attacker-controlled mathematical expressions can use an inherited trust value to enable trusted rendering and produce links capable of user-interaction cross-site scripting or loading attacker-selected external resources in a consuming application that inserts unsanitized KaTeX output into a page. KaTeX does not itself create the prototype pollution, and rendering an expression alone does not execute script. This issue is fixed in version 0.18.2.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.30%

Chance of exploitation in the next 30 days

Percentile

23%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.30% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard35 products
  • code-server< 4.140.0-r4
  • commercial-gitlab-rails-ee-19.1< 19.1.7-r3
  • commercial-gitlab-rails-ee-19.2< 19.2.7-r1
  • commercial-gitlab-rails-ee-19.3< 19.3.3-r1
  • commercial-gitlab-rails-ee-19.4< 19.4.1-r1
Wolfi4 products
  • code-server< 4.140.0-r4
  • jupyter-base-notebook< 7.6.3-r2
  • langfuse-3-workerAll versions (No fix recorded) | < 3.225.12-r2
  • renovateAll versions (No fix recorded) | < 44.133.0-r4
Debian1 product
  • node-katexAll versions (No fix recorded) | < 0.16.10+~cs6.1.0-10
Katex1 product
  • katex≥ 0.11.0, < 0.18.2
Npm1 product
  • katex≥ 0.11.0, < 0.18.2
Opensuse1 product
  • python-jupyterlab-templates&distro=openSUSE Tumbleweed< 0.5.3-3.1
Ubuntu1 product
  • node-katexAll versions (No fix recorded)

7 vendors · 44 products

References

11 links
Show all 11 references