OSV-2026-736 Heap-buffer-overflow in coap_pdu_parse_header
A heap buffer overflow in the CoAP library allows remote attackers to cause denial of service or potentially execute code via crafted packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is OSV-2026-736?
OSV-2026-736 is a memory corruption vulnerability in libcoap, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=512517700
Crash type: Heap-buffer-overflow READ 1
Crash state:
coap_pdu_parse_header
coap_pdu_parse2
coap_pdu_parse
Which versions are affected by OSV-2026-736?
1 open source package ship an affected version, including libcoap.
| Package | Affected | Fixed in |
|---|---|---|
libcoap OSS-Fuzz | All versions | None |
How do I fix OSV-2026-736?
No fix has been published for OSV-2026-736 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is OSV-2026-736 being exploited?
There is no known exploitation of OSV-2026-736 in the wild and no public exploit code.