CVE-2025-53538 Suricata's mishandling of data on HTTP2 stream 0 can lead to resource starvation
Attackers can cause resource starvation and loss of visibility in Suricata by sending malformed HTTP/2 data on stream 0.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-53538?
CVE-2025-53538 is a high-severity denial of service vulnerability in Oisf Suricata, published on 22 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Suricata is a network IDS, IPS and NSM engine developed by the OISF (Open Information Security Foundation) and the Suricata community. In versions 7.0.10 and below and 8.0.0-beta1 through 8.0.0-rc1, mishandling of data on HTTP2 stream 0 can lead to uncontrolled memory usage, leading to loss of visibility. Workarounds include disabling the HTTP/2 parser, and using a signature like drop http2 any any -> any any (frame:http2.hdr; byte_test:1,=,0,3; byte_test:4,=,0,5; sid: 1;) where the first byte test tests the HTTP2 frame type DATA and the second tests the stream id 0. This is fixed in versions 7.0.11 and 8.0.0.
Which versions are affected by CVE-2025-53538?
It affects 1 product.
Products include Oisf Suricata.
How do I fix CVE-2025-53538?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-53538 being exploited?
There is no known exploitation of CVE-2025-53538 in the wild and no public exploit code.
Other vulnerabilities in Oisf Suricata
Sources
Also known as DEBIAN-CVE-2025-53538, GHSA-qrr7-crgj-cmh3, UBUNTU-CVE-2025-53538.