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CVE-2021-20308Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is…
- 9.8CriticalCVSS base score
- 2.5%Exploitation in 30 daysEPSS · top 15% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is similar to CVE-2017-9181.
Timeline
ID reserved
By redhat
- 4 months later
· 4 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 2.5% · top 15% of all CVEs (13 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
htmldoc
- affected htmldoc 1.9.11 and older
References
References3
- https://github.com/michaelrsweet/htmldoc/issues/423 (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.redhat.com/show_bug.cgi?id=1946289 (opens in a new tab)x_refsource_MISCx_transferred
- [debian-lts-announce] 20210701 [SECURITY] [DLA 2700-1] htmldoc security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-7733 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-20308)Record last updated .