CVE-2017-16931 — parser
parser.c in libxml2 before 2.9.5 mishandles parameter-entity references because the NEXTL macro calls the xmlParserHandlePEReference function in the case of a '%' character in a DTD name.
Published
2017-11-23T21:29:00.390
Last modified
2026-10-14T07:16:39.460
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
01What is this vulnerability?
parser.c in libxml2 before 2.9.5 mishandles parameter-entity references because the NEXTL macro calls the xmlParserHandlePEReference function in the case of a '%' character in a DTD name.
02Affected products
No structured affected-product list available — see references below for vendor advisories.
03Active exploitation status
Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.
04Recommended remediation
- Patch to a fixed version listed in the vendor advisory (see references below).
- Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
- Hunt historical logs for exploitation indicators — see Detection signatures below.
05Technical details
For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.
06Detection signatures
Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.
07Related CVEs
No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.
08Timeline
- Published: 2017-11-23T21:29:00.390
- Last modified: 2026-10-14T07:16:39.460
09References
- xmlsoft.org — http://xmlsoft.org/news.html
- bugzilla.gnome.org — https://bugzilla.gnome.org/show_bug.cgi?id=766956
- github.com — https://github.com/GNOME/libxml2/commit/e26630548e7d138d2c560844c43820b6767251e3
- lists.debian.org — https://lists.debian.org/debian-lts-announce/2017/11/msg00041.html
- www.oracle.com — https://www.oracle.com//security-alerts/cpujul2021.html
- xmlsoft.org — http://xmlsoft.org/news.html
- bugzilla.gnome.org — https://bugzilla.gnome.org/show_bug.cgi?id=766956
- github.com — https://github.com/GNOME/libxml2/commit/e26630548e7d138d2c560844c43820b6767251e3
- lists.debian.org — https://lists.debian.org/debian-lts-announce/2017/11/msg00041.html
- www.oracle.com — https://www.oracle.com//security-alerts/cpujul2021.html
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