CVE-2021-41816: fedoraproject fedora Integer Overflow or Wraparound
Vulnerability summary
CVE-2021-41816 is a critical (CVSS 9.8) Integer Overflow or Wraparound vulnerability in fedoraproject fedora. EPSS estimates a 4.90% chance of exploitation in the next 30 days, higher than 92.1% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (reference, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 12 · Related 10Timeline
- 06-02-2022PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · RubygemsEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
4.90%
Chance of exploitation in the next 30 days
Percentile
92%
Versus all other CVEs
30-day change
Increase +0.13 pp
From 4.77% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundExploit Reference (ruby-lang.org)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu2 products
- ruby2.7< 2.7.0-5ubuntu1.6
- ruby3.0< 3.0.2-7ubuntu2
Alpine1 product
- ruby< 2.7.5-r0 | < 3.0.3-r0
Debian1 product
- ruby2.7< 2.7.4-1+deb11u1
Fedoraproject1 product
- fedoraEOL34 | 35
Ruby-lang1 product
- cgi< 0.3.1 | ≤ 0.2.0 | ≤ 0.1.0
RubyGems1 product
- cgi≥ 0.3.0, < 0.3.1 | ≥ 0.2.0, < 0.2.1 | < 0.1.0.1
6 vendors · 7 products
References
25 links- www.ruby-lang.org/en/news/2021/11/24/buffer-overrun-in-cgi-escape_html-cve-2021-41816/REPORTExploitVendor Advisory
- security.netapp.com/advisory/ntap-20220303-0006/Third Party Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
Show all 25 references
- github.com/ruby/cgiPACKAGE