anacrolix/torrent through 1.61.0 Memory Exhaustion via Unbounded HTTP Tracker Response
Affects anacrolix/torrent through 1.61.0 when a client fetches an HTTP tracker set by an attacker in a torrent file or magnet link. No fix is listed in the checked facts.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fix or patch referenced
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects anacrolix/torrent through version 1.61.0 Attacker controls an HTTP tracker referenced by a torrent file or magnet link
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 19/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The anacrolix/torrent library's HTTP tracker code buffers announce and scrape responses without size limits, so a malicious tracker can send oversized or gzip-compressed replies that exhaust process memory and crash the client. An attacker can reach this remotely without logging in, but a user must first open a torrent file or magnet link that points to the attacker's HTTP tracker.
Read the original description
anacrolix/torrent through 1.61.0 contains a memory exhaustion vulnerability in the tracker/http package that allows malicious trackers to crash clients by returning unbounded responses. Attackers controlling an HTTP tracker in a torrent file or magnet link can return huge or gzip-compressed announce or scrape responses that Client.Announce and Client.Scrape buffer without limits, exhausting process memory.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.1/10CVSS 7.1
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
Affects anacrolix/torrent through version 1.61.0 Attacker controls an HTTP tracker referenced by a torrent file or magnet linkApply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- anacrolix torrent
through 1.61.0
Evidence 5
- Patch
- Patch
- Repository
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123096
Is CVE-2026-123096 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A malicious HTTP tracker can return a very large or gzip-compressed response, and the client reads it without a size limit. This can use up the process's memory and crash the client.Source: vulncheck.com
Which versions are affected by CVE-2026-123096?
torrent: through 1.61.0.Source: cve.now feed data
Am I affected, and how do I check?
The facts list anacrolix/torrent through version 1.61.0 as affected. The bug needs an HTTP tracker that an attacker controls, referenced by a torrent file or magnet link. To check a version, look at the anacrolix/torrent version your build uses, such as the module version in your go.mod file.Source: vulncheck.com
How do I fix CVE-2026-123096?
The checked facts do not name a fixed release, so no upgrade target can be given. Check the project's releases for a version newer than 1.61.0 before deciding on an upgrade.Source: vulncheck.com