CVE-2020-1957 [Critical] | Authentication Bypass in Shiro

CVE-2020-1957 is rated High Risk (76.5/100): CVSS Critical severity, with high exploitation likelihood (EPSS 88.60%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +2.50% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-04	86.10%	88.60%	+2.50%
2	2026-03-01	88.60%	86.10%	-2.50%
3	2026-02-16	—	88.60%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-04

86.10%

88.60%

+2.50%

2026-03-01

88.60%

86.10%

-2.50%

2026-02-16

—

88.60%

—

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]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/A:P` 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:P) Partial availability impact.	10.0	6.4	[email protected]

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]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P 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:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2020-1957

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2020-1957 not yet assigned 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-2020-1957
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2020-1957
`ubuntu`	medium	CVE-2020-1957 medium priority: Ubuntu including 1 source packages (shiro), 17 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 7, not-affected 5, released 3, DNE 1, needs-triage 1.	https://ubuntu.com/security/CVE-2020-1957

Affected software / configurations for CVE-2020-1957

Vendor	Product	Version	Raw CPE
apache	shiro	< 1.5.2	cpe:2.3:a:apache:shiro::::::::
debian	debian_linux	8.0	cpe:2.3:o:debian:debian_linux:8.0:::::::*

References for CVE-2020-1957

URL	Tags
https://lists.apache.org/thread.html/r17f371fc89d34df2d0c8131473fbc68154290e1be238895648f5a1e6%40%3Cdev.shiro.apache.org%3E	Mailing List Vendor Advisory
https://lists.apache.org/thread.html/r2d2612c034ab21a3a19d2132d47d3e4aa70105008dd58af62b653040%40%3Ccommits.shiro.apache.org%3E
https://lists.apache.org/thread.html/rab1972d6b177f7b5c3dde9cfb0a40f03bca75f0eaf1d8311e5762cb3%40%3Ccommits.shiro.apache.org%3E
https://lists.apache.org/thread.html/rb3982edf8bc8fcaa7a308e25a12d294fb4aac1f1e9d4e14fda639e77%40%3Cdev.geode.apache.org%3E
https://lists.apache.org/thread.html/rc64fb2336683feff3580c3c3a8b28e80525077621089641f2f386b63%40%3Ccommits.camel.apache.org%3E
https://lists.apache.org/thread.html/rc8b39ea8b3ef71ddc1cd74ffc866546182683c8adecf19c263fe7ac0%40%3Ccommits.shiro.apache.org%3E
https://lists.debian.org/debian-lts-announce/2020/04/msg00014.html	Mailing List Third Party Advisory

URL

CVE-2020-1957

Exploit prediction scoring system (EPSS) score for CVE-2020-1957

Common vulnerability scoring system (CVSS) metrics for CVE-2020-1957

Weakness enumeration for CVE-2020-1957

GitHub Security Advisory for CVE-2020-1957

OS Trackers for CVE-2020-1957

Affected software / configurations for CVE-2020-1957

References for CVE-2020-1957