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VulnerabilityPublished Updated

CVE-2026-85077: sanic · HTTP Request/Response Splitting

Affects sanicSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 25.12.1 or 24.12.1 soon.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 25.12.1, 24.12.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

Upgrade sanic to 25.12.1 or 24.12.1.

Affected software

ProductAffectedFixed in
sanic-orgsanicAffected
  • >=25.12.0 <25.12.1
Fixed in
  • 25.12.1
sanic-orgsanicAffected
  • <24.12.1
Fixed in
  • 24.12.1
PyPIsanicpkg:pypi/sanicOther threatsAffected
  • <24.12.1
  • >=25.12.0 <25.12.1
Fixed in
  • 24.12.1
  • 25.12.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Sanic to version 24.12.1 or later, or to version 25.12.1 or later. These versions contain the official fix that properly neutralizes CRLF sequences in HTTP headers. No other mitigation is required once patched.

Description

Sanic is an opensource python web server/framework. Prior to version 24.12.1, and in version 25.12.0, the HTTP/1.1 response pipeline in sanic/response/types.py serializes response header names and values without rejecting carriage-return or line-feed characters. Applications that place attacker-controlled data in response.headers, file(..., filename=...), or cookie path and domain attributes can therefore emit injected headers and may split responses. Depending on application and proxy behavior, this can enable session fixation through injected cookies, cache poisoning, or security-header corruption. This issue is fixed in versions 24.12.1 and 25.12.1.

References

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