OSV-2026-959 Heap-use-after-free in Wt::Http::Request::parseFormUrlEncoded
A heap-use-after-free in the Wt library's HTTP request parser allows attackers to cause crashes or potentially execute code via crafted requests.
- 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-2026-959?
OSV-2026-959 is an use after free vulnerability in wt, published on 23 Jun 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=526224351
Crash type: Heap-use-after-free READ 8
Crash state:
Wt::Http::Request::parseFormUrlEncoded
Wt::CgiParser::parse
fuzz-cgi.C
Which versions are affected by OSV-2026-959?
1 open source package ship an affected version, including wt.
| Package | Affected | Fixed in |
|---|---|---|
wt OSS-Fuzz | All versions | None |
How do I fix OSV-2026-959?
No fix has been published for OSV-2026-959 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is OSV-2026-959 being exploited?
There is no known exploitation of OSV-2026-959 in the wild and no public exploit code.