CVE-2021-25219
Lame cache can be abused to severely degrade resolver performance
Public exploit available. Not confirmed exploited in the wild yet. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
0 sources with a proof of concept or module.
Exploit links, PoCs and Metasploit modules after sign-in- EPSS
11% chance of exploitation activity in the next 30 days, which ranks it in the 96th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
13 events over 1758 days, from the signal feeds we watch.
- EPSS band change0 → moderateepss band change
- EPSS band changemoderate → low
- EPSS band changemoderate → low
- EPSS band changemoderate → low
- OpenVAS check added
- EPSS band changemoderate → low
Affected products
And 12 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Scored 5.3 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability LowReduced performance or intermittent disruption of service
Weaknesses
Sources
References in the record
- cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- kb.isc.org/v1/docs/cve-2021-25219
- lists.debian.org/debian-lts-announce/2021/11/msg00001.html
And 105 more references. See all after sign-in
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