CVE-2020-17523

Apache Shiro before 1.7.1, when using Apache Shiro with Spring, a specially crafted HTTP request may cause an authentication bypass.

Published: 2021-02-03 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2020-17523 is rated High Risk (72.9/100): CVSS Critical severity, with high exploitation likelihood (EPSS 88.77%, 99th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-17523

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 89.88% 88.77% -1.11%
2 2025-11-18 88.77% 89.88% +1.11%
3 2025-04-22 88.77%

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-17523

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 5.9 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:C)
Complete availability impact.
10.0 8.5 [email protected]

Weakness enumeration for CVE-2020-17523

GitHub Security Advisory for CVE-2020-17523

GHSA-v98j-7crc-wvrj · Severity: critical · Ecosystem: maven — Authentication bypass in Apache Shiro

OS Trackers for CVE-2020-17523

vendor priority summary link
debian unimportant CVE-2020-17523 unimportant priority: Debian including 1 source packages (shiro), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2020-17523
redhat high https://access.redhat.com/security/cve/CVE-2020-17523
ubuntu medium CVE-2020-17523 medium priority: Ubuntu including 1 source packages (shiro), 14 status rows across 14 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): ignored 6, not-affected 6, DNE 1, released 1. https://ubuntu.com/security/CVE-2020-17523

Affected software / configurations for CVE-2020-17523

Vendor Product Version Raw CPE
apache shiro < 1.7.1 cpe:2.3:a:apache:shiro:*:*:*:*:*:*:*:*

References for CVE-2020-17523

URL Tags
https://lists.apache.org/thread.html/r5b93ddf97e2c4cda779d22fab30539bdec454cfa5baec4ad0ffae235%40%3Cgitbox.activemq.apache.org%3E
https://lists.apache.org/thread.html/r679ca97813384bdb1a4c087810ba44d9ad9c7c11583979bb7481d196%40%3Cdev.shiro.apache.org%3E
https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3E
https://lists.apache.org/thread.html/r852971e28f54cafa7d325bd7033115c67d613b112a2a1076817390ac%40%3Cdev.shiro.apache.org%3E
https://lists.apache.org/thread.html/r9d93dfb5df016b1a71a808486bc8f9fbafebbdbc8533625f91253f1d%40%3Cdev.shiro.apache.org%3E
https://lists.apache.org/thread.html/rce5943430a6136d37a1f2fc201d245fe094e2727a0bc27e3b2d43a39%40%3Cdev.shiro.apache.org%3E Mailing List Vendor Advisory
https://lists.apache.org/thread.html/rd4b613e121438b97e3eb263cac3137caddb1dbd8f648b73a4f1898a6%40%3Cissues.activemq.apache.org%3E
https://lists.apache.org/thread.html/re25b8317b00a50272a7252c4552cf1a81a97984cc2111ef7728e48e0%40%3Cdev.shiro.apache.org%3E
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