# Datadog dd-trace-py: ReDoS in URL query string obfuscation

Advisory record · `GHSA-3633-r77q-h3v3`

- **Identifiers:** `GHSA-3633-r77q-h3v3` · `CVE-2026-116588`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 27 Oct 2026, 15:37 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `ddtrace` (PyPI): affected `>=1.5.0, <3.19.9 || >=4.0.0, <4.15.6`; fixed in `3.19.9`, `4.15.6`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.7 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0047, the 40th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 26 Oct 2026, 21:22 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-116588)
- 26 Oct 2026, 22:16 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-116588)
- 31 Oct 2026, 14:07 UTC: First seen by agentprime
- 31 Oct 2026, 14:07 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3633-r77q-h3v3)

## Sources

- [GitHub Advisory Database: GHSA-3633-r77q-h3v3](https://github.com/advisories/GHSA-3633-r77q-h3v3)
- [OSV: GHSA-3633-r77q-h3v3](https://osv.dev/vulnerability/GHSA-3633-r77q-h3v3)
- <https://github.com/DataDog/dd-trace-py/security/advisories/GHSA-3633-r77q-h3v3>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-116588>
- <https://github.com/DataDog/dd-trace-py/pull/20857>
- <https://github.com/DataDog/dd-trace-py/pull/20862>
- <https://github.com/DataDog/dd-trace-py/pull/20880>
- <https://github.com/DataDog/dd-trace-py/commit/63ddc3cb07d8813ded7a8b3ab5b8d0f5470e4bfd>
- <https://github.com/DataDog/dd-trace-py/commit/83ea39845dd95bfb9b8e247c62b3d22fc5dce1ce>
- <https://github.com/DataDog/dd-trace-py/commit/a6d73607ea45ecd67152630f64b0945556972ed8>
- <https://github.com/DataDog/dd-trace-py>
- <https://github.com/DataDog/dd-trace-py/releases/tag/v3.19.9>
- <https://github.com/DataDog/dd-trace-py/releases/tag/v4.15.6>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-3633-r77q-h3v3>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-3633-r77q-h3v3/>. Everything for agents: <https://agentprime.io/llms.txt>.