CVE-2026-43974
Unsolicited 101 response forces gun to raw protocol mode.
Is CVE-2026-43974 being exploited?
Not confirmed. CVE-2026-43974 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.48% probability of exploitation in the next 30 days.
How severe is CVE-2026-43974?
CVE-2026-43974 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-43974?
Yes. A fix has been recorded for CVE-2026-43974. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-43974 affect?
CVE-2026-43974 affects gun_http (gun), gun (Elixir/Erlang). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-43974?
Upgrade to gun >= 2.4.0
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Forces client into raw protocol mode via unsolicited 101; bypasses HTTP framing; unbounded data floods BEAM memory, risking VM crash.
Patch when possible
- affected>= 2.0.0 and < 2.4.0
- affected>= a3c2edbb8c807717e2f10520c6cf1e77a62eab2e and < 5b48068c29ce5e112cb149b5857c7d4dc319a81b
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.