CVE-2026-85077Public exploitNetwork attack vectorHinoki check available

Header injection via missing CRLF validation

Published Sep 17, 2026 · Updated Sep 21, 2026

HTTP response header injection in Sanic before 24.12.1 and in 25.12.0 allows remote attackers to inject headers through reflected input. The HTTP/1.1 serializer in sanic/response/types.py writes header names and values without rejecting carriage-return or line-feed characters. Exploitation requires an application to place attacker-controlled data in response headers, filenames, or cookie attributes, enabling injected cookies, cache poisoning, security-header corruption, or response splitting.

CVSS severity8.2
High
EPSS probability0.48%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

HTTP response header injection in Sanic before 24.12.1 and in 25.12.0 allows remote attackers to inject headers through reflected input. The HTTP/1.1 serializer in sanic/response/types.py writes header names and values without rejecting carriage-return or line-feed characters. Exploitation requires an application to place attacker-controlled data in response headers, filenames, or cookie attributes, enabling injected cookies, cache poisoning, security-header corruption, or response splitting.

The record

CVE
CVE-2026-85077
Published
Sep 17, 2026
Updated
Sep 21, 2026
Vendor
Sanic Community Organization
Product
Sanic
Classifications
CWE-113, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 24.12.1
  2. Affected versionversion=>= 25.12.0, < 25.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sanic Community Organization · Sanicversion=< 24.12.1; version=>= 25.12.0, < 25.12.1

Published CVSS scores

8.2GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
T1190Exploit Public-Facing Application

Public exploit references

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Technologies

Your stack

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Your stack

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