Quick answers
- Is CVE-2026-113799 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-113799 being exploited in the wild.
- How severe is CVE-2026-113799?
- Medium severity, with a CVSS score of 5.3, published 21 October 2026.
- Which products and versions are affected?
- Abdolence Slack Morphism 1.0.0 through 2.27.0; slack-morphism (crates.io) >= 1.0.0, <= 2.27.0, SEMVER:introduced=1.0.0,fixed=2.28.0; Slack Morphism project Slack-Morphism 2.26.0 through 2.27.0; likely all versions from 0.10.0 onward based on git history.
- Is there a fix for CVE-2026-113799?
- Yes. slack-morphism (crates.io): upgrade to 2.28.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-113799 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-113799?
- Check whether you run Abdolence Slack Morphism, slack-morphism (crates.io) or Slack Morphism project Slack-Morphism 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.
How to fix
- slack-morphism (crates.io): upgrade to 2.28.0 or later
cargo update -p slack-morphism
Technical details
The vulnerability exists in the SlackEventWrongSignatureError exception handler, which exposes the computed correct HMAC signature in its Debug and Display representations. An attacker can send a request with an invalid signature, retrieve the correct signature from application error logs, and replay the same request within the five-minute freshness window to pass verification without knowing the Slack signing secret. This requires network access to the callback endpoint and read access to application logs.
Affected products
- abdolence Slack Morphism 1.0.0 through 2.27.0
Identifiers
- CVE-2026-113799
- GHSA-26w4-8w32-4x3v
Timeline
- 2026-10-21: disclosed
- 2026-09-09: patched