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CVE-2020-13933

51
FAUCET Score

CVE-2020-13933 describes an authentication bypass vulnerability in Apache Shiro versions prior to 1.6.0, affecting Apache Shiro and Debian Linux distributions utilizing it. This high-severity flaw (CVSS 7.5) allows unauthenticated attackers to bypass authentication with a specially crafted HTTP request, potentially leading to unauthorized access. Despite its high risk score and potential for critical impact (C:H), there is currently no public exploit code available, no evidence of active exploitation, and minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.6.0CPE matchmatch criteria
cpe:2.3:a:apache:shiro:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
48.02%
Probability of exploitation in next 30 days
EPSS Percentile
98.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.4802 is in the 98th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

mavenpatch availablevia ghsa
Product: org.apache.shiro:shiro-coreFixed in: 1.6.0
redhatpatch availablevia redhat_api
Product: Red Hat Fuse 7.8.0Fixed in: shiro-core
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Fuse/AMQ 6.3.18Fixed in: shiro-core
View patch

Vendor Advisories (2)

mavenGHSA-2vgm-wxr3-6w2jhigh

Authentication bypass in Apache Shiro

May 7, 2021
redhatCVE-2020-13933Important

shiro: specially crafted HTTP request may cause an authentication bypass

Aug 17, 2020

References

lists.apache.org / thread.html/r18b45d560d76c4260813c802771cc9678aa651fb8340e09366bfa198%40%3Cdev.geode.apache.org%3E
lists.apache.org / thread.html/r4506cedc401d6b8de83787f8436aac83956e411d66848c84785db46d%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r4c1e1249e9e1acb868db0c80728c13f448d07333da06a0f1603c0a33%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r539f87706094e79c5da0826030384373f0041068936912876856835f%40%3Cdev.shiro.apache.org%3E
Mailing ListVendor Advisory
lists.apache.org / thread.html/r575301804bfac87a064359cf4b4ae9d514f2d10db7d44120765f4129%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r6ea0224c1971a91dc6ade1f22508119a9c3bd56cef656f0c44bbfabb%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r70098e336d02047ce4d4e69293fe8d558cd68cde06f6430398959bc4%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r70b907ccb306e9391145e2b10f56cc6914a245f91720a17a486c020a%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r8097b81905f2a113ebdf925bcbc6d8c9d6863c807c9ee42e1e7c9293%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r852971e28f54cafa7d325bd7033115c67d613b112a2a1076817390ac%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r9d93dfb5df016b1a71a808486bc8f9fbafebbdbc8533625f91253f1d%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/r9ea6d8560d6354d41433ad006069904f0ed083527aa348b5999261a7%40%3Cdev.geode.apache.org%3E
lists.apache.org / thread.html/rb47d88af224e396ee34ffb88ee99fb6d04510de5722cf14b7137e6bc%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/rb5edf49cd1451475dbcf53826ba6ef1bb7872dd6493d6112eb0c2bad%40%3Cdev.shiro.apache.org%3E
lists.apache.org / thread.html/re25b8317b00a50272a7252c4552cf1a81a97984cc2111ef7728e48e0%40%3Cdev.shiro.apache.org%3E
lists.debian.org / debian-lts-announce/2021/08/msg00002.html
Mailing ListThird Party Advisory