# CVE-2026-68956: Erlang/OTP SSH unbounded session channel allocation denial of service

Source: https://junglewise.ai/threats/cve-2026-68956-allocation-of-resources-without-limits-or-throttling  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-68956 · Severity: info · Published 2026-09-22

The SSH daemon in Erlang/OTP fails to enforce limits on idle session channels, allowing an authenticated attacker to exhaust server memory by repeatedly opening session channels that are never assigned handlers. This causes the entire Erlang node to run out of memory and crash, affecting all applications running on that node and resulting in a denial of service.

Technologies: [Erlang OTP](https://junglewise.ai/threats/technologies/otp). Vendors: [Erlang](https://junglewise.ai/threats/vendors/erlang).

## Quick answers

**Is CVE-2026-68956 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-68956 being exploited in the wild.

**How severe is CVE-2026-68956?** Informational severity, published 22 September 2026.

**Which products and versions are affected?** Erlang OTP 18.1.2 through 27.3.4.17, 28.0.0 through 28.5.0.6, 29.0.0 through 29.1.0.

**Is there a fix for CVE-2026-68956?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-68956 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-68956?** Check whether you run Erlang OTP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in ssh_connection:handle_msg/4, which creates #channel{} records and stores them in an ETS cache without enforcing the max_channels limit; the limit only checks supervisor children, so channels without handlers bypass the check entirely. An authenticated remote attacker can open many idle session channels over a single SSH connection to accumulate memory until the emulator terminates. The attack requires prior authentication and network access to the SSH daemon.

## Affected products

- Erlang OTP 18.1.2 through 27.3.4.17, 28.0.0 through 28.5.0.6, 29.0.0 through 29.1.0

## Timeline

- 2026-09-22: disclosed
- 2026-09-24: advisory: CNA advisory published

## References

- [https://github.com/](https://github.com/)
- [https://cna.erlef.org/cves/CVE-2026-68956.html](https://cna.erlef.org/cves/CVE-2026-68956.html)

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