CVE-2026-33169
Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
CVE-2026-33169- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-400, CWE-1333
- Updated
- 2026-11-02
EUVDEUVD-2026-14622
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
EUVD-2026-14622- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-cg4j-q9v8-6v38
Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
Impact
NumberToDelimitedConverter used a regular expression with gsub! to insert thousands delimiters. This could produce quadratic time complexity on long digit strings.
Releases
The fixed releases are available at the normal locations.
Credit
This issue was responsibly reported by Hackerone researcher scyoon.
- Record
GHSA-cg4j-q9v8-6v38- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-400, CWE-1333
- Updated
- 2026-11-02
NVD
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
CVE-2026-33169- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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 - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400, CWE-1333
- Updated
- 2026-11-02
OSV
Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
CVE-2026-33169- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-1333, CWE-400
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-33169
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
DEBIAN-CVE-2026-33169- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
OSVGHSA-cg4j-q9v8-6v38
Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
Impact
NumberToDelimitedConverter used a regular expression with gsub! to insert thousands delimiters. This could produce quadratic time complexity on long digit strings.
Releases
The fixed releases are available at the normal locations.
Credit
This issue was responsibly reported by Hackerone researcher scyoon.
- Record
GHSA-cg4j-q9v8-6v38- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-1333, CWE-400
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-33169
Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. NumberToDelimitedConverter uses a lookahead-based regular expression with gsub! to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and gsub! can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
- Record
UBUNTU-CVE-2026-33169- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
activesupportRubyGems |
8.1.0.beta1 up to 8.1.2.1 | 8.1.2.1 |
activesupportRubyGems |
8.0.0.beta1 up to 8.0.4.1 | 8.0.4.1 |
activesupportRubyGems |
before 7.2.3.1 | 7.2.3.1 |
railsDebian:12 |
before 2:6.1.7.10+dfsg-1~deb12u3, plus listed versions 2:6.1.7.10+dfsg-1~deb12u12:6.1.7.10+dfsg-1~deb12u22:6.1.7.3+dfsg-12:6.1.7.3+dfsg-102:6.1.7.3+dfsg-11 Show 12 moreShow less2:6.1.7.3+dfsg-122:6.1.7.3+dfsg-132:6.1.7.3+dfsg-22:6.1.7.3+dfsg-2~deb12u12:6.1.7.3+dfsg-32:6.1.7.3+dfsg-42:6.1.7.3+dfsg-52:6.1.7.3+dfsg-62:6.1.7.3+dfsg-72:6.1.7.3+dfsg-7~exp12:6.1.7.3+dfsg-82:6.1.7.3+dfsg-9 |
2:6.1.7.10+dfsg-1~deb12u3 |
railsDebian:13 |
before 2:7.2.2.2+dfsg-2~deb13u2, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-12:7.2.2.2+dfsg-2~deb13u1 |
2:7.2.2.2+dfsg-2~deb13u2 |
railsDebian:14 |
before 2:7.2.3.1+dfsg-1, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-12:7.2.2.2+dfsg-22:7.2.2.2+dfsg-2~deb13u12:7.2.2.2+dfsg-2~deb13u22:7.2.3+dfsg-12:7.2.3+dfsg-22:7.2.3+dfsg-3 |
2:7.2.3.1+dfsg-1 |
activesupportRubyGems |
8.1.0.beta1 up to 8.1.2.1, plus listed versions 8.1.08.1.0.rc18.1.18.1.2 |
8.1.2.1 |
activesupportRubyGems |
8.0.0.beta1 up to 8.0.4.1, plus listed versions 8.0.08.0.0.18.0.0.rc18.0.0.rc28.0.1 Show 4 moreShow less8.0.28.0.2.18.0.38.0.4 |
8.0.4.1 |
activesupportRubyGems |
before 7.2.3.1, plus listed versions 1.0.01.0.11.0.21.0.31.0.4 Show 45 moreShow less1.1.01.1.11.2.11.2.21.2.31.2.41.2.51.3.01.3.11.4.01.4.11.4.21.4.31.4.42.0.02.0.12.0.22.0.42.0.52.1.02.1.12.1.22.2.22.2.32.3.102.3.112.3.122.3.142.3.152.3.162.3.172.3.182.3.22.3.32.3.42.3.52.3.62.3.6.pre2.3.72.3.82.3.8.pre12.3.92.3.9.pre3.0.03.0.0.beta |
7.2.3.1 |
railsUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 2:4.1.10-12:4.2.5-12:4.2.5.1-12:4.2.5.2-22:4.2.6-12:4.2.6-1ubuntu0.1~esm12:4.2.6-1ubuntu0.1~esm2 |
None known |
Show 7 moreShow less
| Package | Affected | Fixed |
|---|---|---|
railsUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 2:4.2.9-22:4.2.9-42:4.2.10-0ubuntu42:4.2.10-0ubuntu4+esm12:4.2.10-0ubuntu4+esm2 |
None known |
railsUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 2:5.2.2.1+dfsg-1ubuntu12:5.2.3+dfsg-32:5.2.3+dfsg-3ubuntu0.1~esm1 |
None known |
railsUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 2:6.0.3.7+dfsg-22:6.1.4.1+dfsg-8ubuntu22:6.1.4.1+dfsg-8ubuntu2+esm1 |
None known |
railsUbuntu:24.04:LTS |
All versions, plus listed versions 2:6.1.7.3+dfsg-2build12:6.1.7.3+dfsg-3 |
None known |
railsUbuntu:25.10 |
All versions, plus listed versions 2:6.1.7.3+dfsg-72:7.2.2.1+dfsg-7 |
None known |
railsUbuntu:26.10 |
All versions, plus listed versions 2:7.2.3+dfsg-22:7.2.3.2+dfsg-2 |
None known |
railsUbuntu:26.04:LTS |
All versions, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-22:7.2.3+dfsg-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-33169 is a medium vulnerability (CVSS 6.9) in Rubyonrails Rails, published March 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.66%, the 51st percentile. Fixed in activesupport 8.1.2.1.
References
github.com/rails/rails/security/advisories/GHSA-cg4j-q9v8-6v38
Show 9 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-33169
security-tracker.debian.org/tracker/CVE-2026-33169
ubuntu.com/security/CVE-2026-33169
cve.org/CVERecord?id=CVE-2026-33169
Left out here: 432 versions. The JSON record has them.