GHSA-C4QC-4Q9P-M9Q9
Vulnerability from github – Published: 2026-02-10 12:30 – Updated: 2026-02-10 14:33Observable Timing Discrepancy vulnerability in Apache Shiro.
This issue affects Apache Shiro: from 1., 2. before 2.0.7.
Users are recommended to upgrade to version 2.0.7 or later, which fixes the issue.
Prior to Shiro 2.0.7, code paths for non-existent vs. existing users are different enough, that a brute-force attack may be able to tell, by timing the requests only, determine if the request failed because of a non-existent user vs. wrong password.
The most likely attack vector is a local attack only. Shiro security model https://shiro.apache.org/security-model.html#username_enumeration discusses this as well.
Typically, brute force attack can be mitigated at the infrastructure level.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.apache.shiro:shiro-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.1.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-23901"
],
"database_specific": {
"cwe_ids": [
"CWE-208"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-10T14:33:33Z",
"nvd_published_at": "2026-02-10T10:15:59Z",
"severity": "LOW"
},
"details": "Observable Timing Discrepancy vulnerability in Apache Shiro.\n\nThis issue affects Apache Shiro: from 1.*, 2.* before 2.0.7.\n\nUsers are recommended to upgrade to version 2.0.7 or later, which fixes the issue.\n\nPrior to Shiro 2.0.7, code paths for non-existent vs. existing users are different enough,\nthat a brute-force attack may be able to tell, by timing the requests only, determine if\nthe request failed because of a non-existent user vs. wrong password.\n\nThe most likely attack vector is a local attack only.\nShiro security model\u00a0 https://shiro.apache.org/security-model.html#username_enumeration \u00a0discusses this as well.\n\nTypically, brute force attack can be mitigated at the infrastructure level.",
"id": "GHSA-c4qc-4q9p-m9q9",
"modified": "2026-02-10T14:33:33Z",
"published": "2026-02-10T12:30:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23901"
},
{
"type": "PACKAGE",
"url": "https://github.com/apache/shiro"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread/mm1jct9b86jvnh3y44tj22xvjtx3xhhh"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/02/08/2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Apache Shiro Affected by an Observable Timing Discrepancy Vulnerability"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.