How to Fix CVE-2026-28810: OTP (Bundle Sibling)

*By Sai Kiran Pandrala*

Last verified: 2026-05-25

CVE-2026-28810 is a sibling vulnerability in the same Erlang OTP advisory bundle as CVE-2026-28808. The same patched build closes every CVE in the bundle, so the remediation procedure for CVE-2026-28810 matches the primary write-up.

What is different about CVE-2026-28810?

Generation of Predictable Numbers or Identifiers vulnerability in Erlang/OTP kernel (inet_res, inet_db modules) allows DNS Cache Poisoning. The built-in DNS resolver (inet_res) uses a sequential, process-global 16-bit transaction ID for UDP queries and does not implement source port randomization. Response validation relies almost entirely on this ID, making DNS cache poisoning practical for an attacker who can observe one query or predict the next ID.

Impact is consistent with the bundle: spoofing of identity or session state. The patched build closes every code path in the advisory in one update.

How to fix CVE-2026-28810

Apply the patched build per the primary write-up: How to Fix CVE-2026-28808.

For a quick check, confirm the running version of OTP:

# Confirm the installed version via your package manager
dpkg -l | grep -i otp   # Debian/Ubuntu
rpm -qa | grep -i otp   # RHEL/CentOS/Rocky

Frequently asked questions

Is CVE-2026-28810 being actively exploited?

Not at the time of writing. It is not listed in CISA's Known Exploited Vulnerabilities catalog. That status can change, so monitor the vendor advisory and the KEV catalog if the system is exposed.

How severe is CVE-2026-28810?

CVSS rates it 6.3 (Medium). Use that score to set your patch priority alongside the other items in your queue.

Do I have to take OTP offline to apply the patch?

It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.

What if my vulnerability scanner still flags CVE-2026-28810 after I patch?

Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.

References

• Official vendor advisory: https://github.com/erlang/otp/security/advisories/GHSA-v884-5jg5-whj8
• NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-28810
• CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Primary write-up: How to Fix CVE-2026-28808

*Written by Sai Kiran Pandrala. Last verified 2026-05-25. Part of the Erlang OTP advisory bundle. Full procedure at how-to-fix-cve-2026-28808.*