Hickory DNS before 0.26.2 DoH Memory Exhaustion via Incomplete Request Bodies
Only affects Hickory DNS versions before 0.26.2 when the DNS-over-HTTPS HTTP/2 server is in use. Fixed in 0.26.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 0.26.2
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 0.26.2.
- 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? →
- 26/100 · 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 before 0.26.2 contains a resource exhaustion vulnerability in its DNS-over-HTTPS HTTP/2 server that lacks sufficient timeouts or limits for incomplete request bodies. Remote attackers can open DoH connections, send incomplete request bodies, and hold connections open to exhaust 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 patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
- Would score about 31 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 0.26.2.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- hickory-dns hickory-dns
fixed in 0.26.2
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123575
Is CVE-2026-123575 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 bug lets remote attackers exhaust server memory by opening DoH connections, sending incomplete request bodies, and holding those connections open. The result is resource consumption on the server.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-123575?
hickory-dns: before 0.26.2.Source: cve.now feed data
Am I affected, and how do I check?
The affected range is all Hickory DNS versions below 0.26.2, and the bug applies when the DNS-over-HTTPS HTTP/2 server is in use. To check, compare the installed hickory-dns version against 0.26.2 and see whether the DoH HTTP/2 server is enabled in the configuration.Source: vulncheck.com, github.com
How do I fix CVE-2026-123575?
Upgrade to hickory-dns 0.26.2 or later, which contains the fix. The facts list no workaround, so the upgrade is the fix to apply.Source: vulncheck.com, github.com