CVE-2026-55865 json
Python Liquid: Infinite loop when parsing malformed `{% case %}` tags
published 2026-06-19 4 mo ago modified 2026-10-25 14 d ago also GHSA-vq2f-vcc9-j8mv , PYSEC-2026-3035 , EUVD-2026-42693
- cvss
- 7.1
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 39%
- public exploits
- 0
- none known
Summary
Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.
Patch / fix
- pypi python-liquid 2.2.1
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| CNA | 4.0 | 7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | python-liquid | <2.2.1 |
2.2.1 |
Affected products
- jg-rp liquid
Classification
- Weakness
-
- CWE-835 Loop with Unreachable Exit Condition
References
- github.com /jg-rp/liquid/commit/26db8931cf35e8433c1ca506fc32c3bb62f743d4
-
github.com
/jg-rp/liquid/security/advisories/GHSA-vq2f-vcc9-j8mv
web
- github.com /jg-rp/liquid/releases/tag/v2.2.1
-
github.com
/jg-rp/liquid
package
-
pypi.org
/project/python-liquid
package
-
github.com
/advisories/GHSA-vq2f-vcc9-j8mv
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-55865
advisory
Sources
- CVE List CVE-2026-55865
- GitHub Advisory GHSA-vq2f-vcc9-j8mv
- NVD CVE-2026-55865
- OSV PYSEC-2026-3035
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.