CVE-2025-8671
CVE-2025-8671
No known exploitation. EPSS puts it in the 89th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
A mismatch caused by client-triggered server-sent stream resets between HTTP/2 specifications and the internal architectures of some HTTP/2 implementations may result in excessive server resource consumption leading to denial-of-service (DoS). By opening streams and then rapidly triggering the server to reset them—using malformed frames or flow control errors—an attacker can exploit incorrect stream accounting. Streams reset by the server are considered closed at the protocol level, even though backend processing continues. This allows a client to cause the server to handle an unbounded number of concurrent streams on a single connection. This CVE will be updated as affected product details are released.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
3.7% chance of exploitation activity in the next 30 days, which ranks it in the 89th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
5 events over 316 days, from the signal feeds we watch.
- OpenVAS check added
- Patch availablerecord updated
- Publishedweakness classified
Affected products
- Enterprise Module for Development ToolsOperating Systems / linux-distro
- Enterprise High Performance Computing (HPC)Operating Systems / linux-distro
- Enterprise DesktopOperating Systems / linux-distro
- Enterprise High Performance ComputingOperating Systems / linux-distro
- Enterprise Module for Dev ToolsOperating Systems / linux-distro
- Enterprise Module for Package HubOperating Systems / linux-distro
- Enterprise ServerOperating Systems / linux-distro
- Enterprise Server for SAP ApplicationsOperating Systems / linux-distro
And 5 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 7.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
References in the record
- github.com/h2o/h2o/commit/4729b661e3c6654198d2cc62997e1af58bef4b80&
- github.com/h2o/h2o/security/advisories/GHSA-mrjm-qq9m-9mjq&
- galbarnahum.com/posts/made-you-reset-intro
And 17 more references. See all after sign-in
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