UBUNTU-CVE-2026-116128: Medium severity ubuntu/starlet vulnerability
Starlet versions from 0.20 before 0.33 for Perl allow memory exhaustion via unbounded buffering when decoding chunked request bodies. The decoder adds each read to one buffer of unconsumed input. Nothing limits the length of a chunk-size line, so a line without a CRLF grows the buffer for as long as the client keeps sending, and the read timeout restarts after every read. The data of a large chunk is also held in the buffer until the whole chunk has arrived. A remote attacker can exhaust a worker's memory with a single request.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Starletto a version that resolves this vulnerability.Fixed in 0.33
Event History
Frequently Asked Questions
Which deployments are exposed?
Deployments using Starlet versions from 0.20 up to, but not including, 0.33 are affected when they decode chunked HTTP request bodies. The issue can be triggered remotely.
What does an attacker need to do to trigger the issue?
An attacker can send a single chunked request with a chunk-size line that never terminates with CRLF, continuing to send data so the unconsumed-input buffer grows. A large chunk can also consume memory because its data remains buffered until the entire chunk arrives.
What is the practical impact on a server?
A single request can exhaust the memory available to a worker. The read timeout does not stop the slow stream because it restarts after each read.