CVE-2021-29262 | Misapplied Zookeeper ACLs can result in leakage of configured authentication and authorization settings

When starting Apache Solr versions prior to 8.8.2, configured with the SaslZkACLProvider or VMParamsAllAndReadonlyDigestZkACLProvider and no existing security.json znode, if the optional read-only user is configured then Solr would not treat that node as a sensitive path and would allow it to be readable. Additionally, with any ZkACLProvider, if the security.json is already present, Solr will not automatically update the ACLs.

Published: 2021-04-13 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-29262 is rated High Risk (68.2/100): CVSS High severity, with high exploitation likelihood (EPSS 26.23%, 96th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +4.58% over the last day, indicating growing attacker interest. 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-2021-29262

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 21.65% 26.23% +4.58%
2 2025-11-18 26.23% 21.65% -4.58%
3 2025-06-19 26.23%

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-29262

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N 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:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-29262

GitHub Security Advisory for CVE-2021-29262

GHSA-jgcr-fg3g-qvw8 · Severity: high · Ecosystem: maven — Improper permission handling in Apache Solr

OS Trackers for CVE-2021-29262

vendor priority summary link
debian unimportant CVE-2021-29262 unimportant priority: Debian including 1 source packages (lucene-solr), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-29262
redhat medium https://access.redhat.com/security/cve/CVE-2021-29262
ubuntu medium CVE-2021-29262 medium priority: Ubuntu including 1 source packages (lucene-solr), 14 status rows across 14 suites (bionic, focal, groovy, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 13, needed 1. https://ubuntu.com/security/CVE-2021-29262

Affected software / configurations for CVE-2021-29262

Vendor Product Version Raw CPE
apache solr < 8.8.2 cpe:2.3:a:apache:solr:*:*:*:*:*:*:*:*

References for CVE-2021-29262

URL Tags
https://lists.apache.org/thread.html/r1171f6417eeb6d5e1206d53e2b2ff2d6ee14026f8b595ef7d8a33b79%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/r1e92a2eff6c47a65c4a6e95e809a9707181de76f8062403a0bea1012%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/r51b29ff62060b67bc9999ded5e252b36b09311fe5a02d27f6de3e4d3%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/r536da4c4e4e406f7843461cc754a3d0a3fe575aa576e2b71a9cd57d0%40%3Cannounce.apache.org%3E Mailing List Vendor Advisory
https://lists.apache.org/thread.html/r7151081abab92a827a607205c4260b0a3d22280b52d15bc909177608%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/r8d35eeb9a470d2682b5bcf3be0b8942faa7e28f9ca5861c058d17fff%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/r9c4ce6903218c92ef2583070e64af5a69e483821c4b3016dc41e3c6f%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/rb6db683903174eaa44ec80cc118a38574319b0d4181f36b61ee6278f%40%3Cdev.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/rbc680cbfd745f22d182158217428a296e8e398cde16f3f428fe4bddc%40%3Coak-issues.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/rd85f87e559ee27e9c69795e3ad93a77621895e0328ea3df41d711d72%40%3Coak-commits.jackrabbit.apache.org%3E
https://lists.apache.org/thread.html/ref84e60192f4bdc3206b247f260513e8d4e71f3e200792f75386d07a%40%3Cdev.jackrabbit.apache.org%3E
https://security.netapp.com/advisory/ntap-20210604-0009/ Third Party Advisory
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