# CVE-2026-90698: memcached out-of-bounds read in ASCII auth tokenizer

Source: https://junglewise.ai/threats/cve-2026-90698-memcached-out-of-bounds-read-in-ascii-auth-tokenizer  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-14. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-90698 · Severity: medium · CVSS 5.3 · Published 2026-09-14

Memcached is an in-memory caching system widely used to accelerate application performance. When ASCII protocol authentication is enabled, a remote attacker can send specially crafted empty newline sequences to trigger an out-of-bounds memory read, causing the service to crash and disrupting dependent applications.

Technologies: [Memcached](https://junglewise.ai/threats/technologies/memcached). Vendors: [Memcached](https://junglewise.ai/threats/vendors/memcached).

## Quick answers

**Is CVE-2026-90698 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-90698 being exploited in the wild.

**How severe is CVE-2026-90698?** Medium severity, with a CVSS score of 5.3, published 14 September 2026.

**Which products and versions are affected?** Memcached 1.6.41, 1.6.42, 1.6.43.

**Is there a fix for CVE-2026-90698?** A patch was published on 2026-09-14: Version 1.6.44 available Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-90698 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-90698?** Check whether you run Memcached 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

An out-of-bounds read vulnerability exists in the try_read_command_asciiauth function of proto_text.c in memcached's ASCII protocol tokenizer when authentication is enabled. The vulnerability occurs when empty newlines are sent to the server, causing the tokenizer to attempt reading a short string without proper bounds checking. The attack is network-accessible and requires no authentication or user interaction. An attacker can remotely crash the memcached service, resulting in denial of service to dependent applications. The vulnerability affects versions 1.6.41, 1.6.42, and 1.6.43, and is fixed in version 1.6.44 by commit af05c9302bba508b736c3da1d5670f63fe8b7db4.

## Affected products

- memcached memcached 1.6.41, 1.6.42, 1.6.43

## Timeline

- 2026-09-14: disclosed
- 2026-09-14: patched: Version 1.6.44 available

## References

- [https://github.com/memcached/memcached/](https://github.com/memcached/memcached/)
- [https://github.com/memcached/memcached/commit/af05c9302bba508b736c3da1d5670f63fe8b7db4](https://github.com/memcached/memcached/commit/af05c9302bba508b736c3da1d5670f63fe8b7db4)

## Related threats

- [Memcached timing side channel in SASL authentication](https://junglewise.ai/threats/cve-2026-47784-memcached-timing-side-channel-in-sasl-authentication)
- [Memcached timing side channel in SASL authentication](https://junglewise.ai/threats/cve-2026-47783-memcached-timing-side-channel-in-sasl-authentication)