CVE-2021-20270
HIGH7.5EPSS 0.22%mediawiki - security update
Published: 4/20/2021Modified: 4/28/2026
Description
An infinite loop in SMLLexer in Pygments versions 1.5 to 2.7.3 may lead to denial of service when performing syntax highlighting of a Standard ML (SML) source file, as demonstrated by input that only contains the "exception" keyword.
Affected packages (9)
- Alpine/py3-pygmentsfrom 0, < 2.7.4-r0
- Debian/mediawikifrom 0, < 1:1.35.2-1
- Debian/mediawikifrom 0, < 1:1.27.7-1~deb9u8
- Debian/mediawikifrom 0, < 1:1.31.14-1~deb10u1
- Debian/pygmentsfrom 0, < 2.7.1+dfsg-2
- Debian/pygmentsfrom 0, < 2.2.0+dfsg-1+deb9u1
- Debian/pygmentsfrom 0, < 2.3.1+dfsg-1+deb10u1
- PyPI/pygments>= 1.5, < 2.7.4
- PyPI/pygments>= 1.5, < 2.7.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (12)
- ADVISORYhttps://github.com/advisories/GHSA-9w8r-397f-prfh
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-20270
- ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2021-20270
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-20270
- PATCHhttps://github.com/pygments/pygments
- WEBhttps://bugzilla.redhat.com/show_bug.cgi?id=1922136
- WEBhttps://github.com/pygments/pygments/commit/f91804ff4772e3ab41f46e28d370f57898700333
- WEBhttps://github.com/pypa/advisory-database/tree/main/vulns/pygments/PYSEC-2021-140.yaml
- WEBhttps://lists.debian.org/debian-lts-announce/2021/05/msg00003.html
- WEBhttps://lists.debian.org/debian-lts-announce/2021/05/msg00006.html
- WEBhttps://www.debian.org/security/2021/dsa-4889
- WEBhttps://www.oracle.com/security-alerts/cpuoct2021.html