CVE-2026-57080 Denial of service in Net::BitTorrent
Remote attackers can exhaust memory in applications using the Net::BitTorrent Perl library by sending maliciously large message length prefixes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-57080?
CVE-2026-57080 is a high-severity denial of service vulnerability in SANKO Net::BitTorrent, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Net::BitTorrent versions through 2.1.0 for Perl allow remote memory exhaustion via an uncapped peer-wire message-length prefix.
The peer-wire framing in _process_messages trusts the 4-byte length prefix sent by a connected peer with no upper bound, while receive_data appends every inbound byte to the input buffer. A peer announces a length prefix of up to about 4 GiB and then streams bytes; the decoder waits until the buffer holds the full message before processing it, so the buffer grows without limit.
Peer connections are unauthenticated, so any peer in the swarm exhausts the downloading process's memory. The largest legitimate message is a 16 KiB piece block, so any announced length far above that is anomalous.
Which versions are affected by CVE-2026-57080?
How do I fix CVE-2026-57080?
No fix has been published for CVE-2026-57080 yet. Limit exposure of the affected software until one is available.
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-2026-57080 being exploited?
There is no known exploitation of CVE-2026-57080 in the wild and no public exploit code.
Sources
Also known as GHSA-7jr6-2jf4-6qc4, GHSA-h9mr-rh28-v9r2.