CVE-2026-15157: undici vulnerable to CRLF Injection via blob-like body 'type' property
Vulnerability summary
CVE-2026-15157 is a medium (CVSS 5.4) vulnerability in nodejs undici. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 18% of scored vulnerabilities.
Not severe (CVSS 4.2, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 5 · Related 4Timeline
- 29-07-2026PublishedVulnerability first disclosed.
- 30-07-2026Last modifiedVulnerability information updated.
Description
undici does not validate the type property of a duck-typed blob-like request body before using it as the Content-Type header on the HTTP/1.1 dispatcher. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, an application that passes a hand-rolled blob-like body (via request, stream, pipeline, or dispatch) whose type is derived from untrusted input allows an attacker to inject CRLF sequences and append arbitrary HTTP headers, potentially smuggling a second request past the upstream. Native Blob objects are safe because their constructor strips CRLF from the type, and fetch is unaffected because it validates headers, but ecosystem libraries that build duck-typed blob shapes from user input can reach the vulnerable path. This is the same defect class as CVE-2022-35948 and CVE-2026-1527, on a header sink that the earlier fixes did not cover. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.
CVSS metrics
7 scores · 7 sources · 1 version- CVE.orgCNA4.2MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:NDiffers
- OSV · UbuntuEcosystem advisory · calculated5.4MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- OSV · DebianEcosystem advisory · calculated5.4MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- OSV · WolfiEcosystem advisory · calculated4.2MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:NDiffers
- OSV · NpmEcosystem advisory · calculated4.2MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:NDiffers
- OSV · ChainguardEcosystem advisory · calculated4.2MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:NDiffers
EPSS trend
Probability
0.26%
Chance of exploitation in the next 30 days
Percentile
18%
Versus all other CVEs
30-day change
Increase +0.07 pp
From 0.19% on 05-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard36 products
- actions-runner< 2.336.0-r5
- code-server< 4.130.0-r5
- commercial-gitlab-rails-ee-19.1< 19.1.7-r3
- commercial-gitlab-rails-ee-19.2< 19.2.7-r1
- commercial-gitlab-rails-ee-19.3< 19.3.3-r1
Wolfi11 products
- code-server< 4.130.0-r5
- langfuse-3< 3.225.0-r3
- langfuse-3-compat< 3.225.7-r6
- langfuse-3-worker< 3.225.0-r3
- npm-12< 12.0.2-r2
Debian1 product
- node-undiciAll versions (No fix recorded) | < 8.9.0+dfsg+~cs3.2.0-1
Nodejs1 product
- undici< 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0
Npm1 product
- undici< 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0
Ubuntu1 product
- node-undiciAll versions (No fix recorded)
Undici1 product
- undici< 6.28.0 | ≥ 7.0.0, < 7.29.0 | ≥ 8.0.0, < 8.9.0
7 vendors · 52 products
References
14 links- github.com/nodejs/undici/security/advisories/GHSA-m8rv-5g2x-5cg5REPORTAdvisoryWEBMitigationVendor Advisory
