CVE-2021-31920: istio
CVSS: 6.5v3.1MediumModified
AliasesGHSA-6q5m-22mq-q2xv
Published 27-05-2021Last modified 03-08-2024
Vulnerability summary
CVE-2021-31920 is a medium (CVSS 6.5) vulnerability in istio. EPSS estimates a 1.32% chance of exploitation in the next 30 days, higher than 70.3% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
6.5/10
010
Medium · v3.1 (NVD)EPSS score
1.32%
0%100%
Low · +0.14 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Advisory lineage
Upstream 0 · Downstream 2Timeline
- 27-05-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
Istio before 1.8.6 and 1.9.x before 1.9.5 has a remotely exploitable vulnerability where an HTTP request path with multiple slashes or escaped slash characters (%2F or %5C) could potentially bypass an Istio authorization policy when path based authorization rules are used.
CVSS metrics
3 scores · 2 sources · 2 versionsMedium 6.5Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:NSourcesAll 2 agree
- OSV · GoEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Medium 4.0Preferred score · NVD (NIST)
AV:N/AC:L/Au:S/C:P/I:N/A:NSourcesSingle source
EPSS trend
Probability
1.32%
Chance of exploitation in the next 30 days
Percentile
70%
Versus all other CVEs
30-day change
+0.14 pp
From 1.17% on 20-09-2026
20-09-202620-10-2026
EPSS score1.32%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (istio.io)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Istio1 product
- istio< 1.8.6 | ≥ 1.9.0, < 1.9.5
Istio.io1 product
- istio< 1.8.6 | ≥ 1.9.0, < 1.9.5
2 vendors · 2 products
