CVE-2021-23437: Regular Expression Denial of Service (ReDoS)
Vulnerability summary
CVE-2021-23437 is a high (CVSS 7.5) Out-of-bounds Read vulnerability in fedoraproject fedora. EPSS estimates a 3.24% chance of exploitation in the next 30 days, higher than 88.3% 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 9 · Related 7Timeline
- 03-09-2021PublishedVulnerability first disclosed.
- 16-09-2024Last modifiedVulnerability information updated.
Description
The package pillow 5.2.0 and before 8.3.2 are vulnerable to Regular Expression Denial of Service (ReDoS) via the getrgb function.
CVSS metrics
8 scores · 6 sources · 3 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · PypiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
3.24%
Chance of exploitation in the next 30 days
Percentile
88%
Versus all other CVEs
30-day change
Increase +0.06 pp
From 3.18% 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 (snyk.io)
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.
Suse5 products
- python-Pillow&distro=HPE Helion OpenStack 8< 4.2.1-3.20.2
- python-Pillow&distro=SUSE OpenStack Cloud 8< 4.2.1-3.20.2
- python-Pillow&distro=SUSE OpenStack Cloud 9< 5.2.0-3.14.1
- python-Pillow&distro=SUSE OpenStack Cloud Crowbar 8< 4.2.1-3.20.2
- python-Pillow&distro=SUSE OpenStack Cloud Crowbar 9< 5.2.0-3.14.1
Alpine2 products
- py-pillow< 6.2.1-r1
- py3-pillow< 7.1.2-r2 | < 7.2.0-r2 | < 8.2.0-r1 | < 8.4.0-r0
Ubuntu2 products
- pillow< 2.3.0-1ubuntu3.4+esm3 | < 3.1.2-0ubuntu1.6+esm1 | < 5.1.0-1ubuntu0.7 | < 7.0.0-4ubuntu0.5 | < 9.0.0-1
- pillow-python2All versions (No fix recorded)
Debian1 product
- pillow< 8.3.2-1
Fedoraproject1 product
- fedoraEOL33 | 34
Mageia1 product
- python-pillow< 8.1.2-1.1.mga8
PyPI1 product
- pillow≥ 5.2.0, < 8.3.2 | < 9e08eb8f78fdfd2f476e1b20b7cf38683754866b | < 8.3.2
Python1 product
- pillow≥ 5.2.0, < 8.3.2
8 vendors · 14 products
References
27 links- snyk.io/vuln/SNYK-PYTHON-PILLOW-1319443WEBAdvisoryREPORTExploitPatchRelease NotesThird Party Advisory
- github.com/python-pillow/Pillow/commit/9e08eb8f78fdfd2f476e1b20b7cf38683754866bWEBFIXPatchThird Party Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
