Hickory DNS 0.24.0 through 0.26.1 Memory Exhaustion via DNS-over-QUIC Requests
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: The checked facts list no fix and no workaround. The trigger is the DNS-over-QUIC server being enabled, so limiting or disabling that server is the only option the facts point to, and the vendor's advisory should be consulted for anything more specific.
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.41% · 35th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 31/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Hickory DNS 0.24.0 through 0.26.1 contains a memory exhaustion vulnerability that allows remote attackers to consume server resources by sending incomplete DNS-over-QUIC request bodies. Attackers can open many connections and send only large length prefixes, causing pre-allocated buffers to persist without timeout and exhausting server memory.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.7/10CVSS 8.7
- No patch5/5No patch listed yet
What would change the score
- Would score about 76 if added to CISA KEV
- Would score about 71 if CISA's SSVC rates exploitation active
- Would score about 36 if advisories confirm default setups are exposed
What to do
Workaround: The checked facts list no fix and no workaround. The trigger is the DNS-over-QUIC server being enabled, so limiting or disabling that server is the only option the facts point to, and the vendor's advisory should be consulted for anything more specific.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- hickory-dns hickory-dns
From 0.24.0 · through 0.26.1
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123576
Is CVE-2026-123576 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The DNS-over-QUIC server reserves a buffer after receiving a length prefix but has no timeout for receiving the rest of the request. Those buffers can stay allocated indefinitely, so a remote attacker can exhaust server memory and cause a denial of service.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-123576?
hickory-dns: from 0.24.0 through 0.26.1.Source: cve.now feed data
Am I affected, and how do I check?
Versions 0.24.0 through 0.26.1 inclusive are affected, but only when the DNS-over-QUIC server is enabled. To check, look at the hickory-dns version in use and whether the DNS-over-QUIC server is turned on in its configuration.Source: vulncheck.com, github.com
How do I fix CVE-2026-123576?
The checked facts do not name a fixed release. Check the hickory-dns project's advisory for the first version that includes the fix, since the affected range ends at 0.26.1.Source: vulncheck.com, github.com
What if there's no patch?
The checked facts list no fix and no workaround. The trigger is the DNS-over-QUIC server being enabled, so limiting or disabling that server is the only option the facts point to, and the vendor's advisory should be consulted for anything more specific.Source: vulncheck.com, github.com