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Fencer Vulns
medium 5.3

CVE-2026-49214 json

guzzlehttp/psr7 has CRLF Injection via URI Host Component

published 2026-06-11 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-36240 , GHSA-hq7v-mx3g-29hw

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Versions prior to 2.10.2 did not reject ASCII control characters, whitespace, or DEL in first-party URI host components. A vulnerable flow is: First, an application accepts a user-controlled URL. Second, the URL is used to construct a PSR-7 `Uri` or `Request`. Third, the host component contains CRLF or another header-unsafe character. Fourth, the host is copied into the PSR-7 `Host` header when no explicit `Host` header is provided. Finally, the request is serialized or sent by an HTTP client that does not independently reject the malformed host. In that flow, an attacker can cause the serialized request to contain additional attacker-controlled header lines. For example, a host containing `"\r\nX-Injected: yes"` can cause the generated `Host` header to span multiple HTTP header lines. Applications are affected when they use user-controlled URLs for outbound HTTP requests, URL forwarding, proxying, crawling, webhook delivery, or similar request-dispatch flows. In deployments involving HTTP/1.1 connection reuse, proxies, gateways, or load balancers, this malformed request may also contribute to request smuggling or cache poisoning, depending on how downstream components parse the request. The issue is patched in `2.10.2` and later. `1.x` is end-of-life and will not receive a patch. As a workaround, validate and reject all untrusted URI strings before constructing PSR-7 `Uri` or `Request` instances. Reject input containing ASCII control characters, whitespace, or DEL, including CRLF, tab, space, NUL, or DEL characters. Applications that forward requests should also ensure the final HTTP client or serializer rejects invalid URI and header data before writing requests to the network.

Patch / fix

  • packagist guzzlehttp/psr7 2.10.2
  • guzzlephp psr-7 2.10.2
  • php-guzzlehttp-psr7 Debian 12 2.4.5-1+deb12u1
  • php-guzzlehttp-psr7 Debian 13 2.7.1-1+deb13u1
  • php-guzzlehttp-psr7 Debian 14 2.10.3-1

debian advisories DEBIAN-CVE-2026-49214

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-49214 updated cvss 5.3

guzzlehttp/psr7: `guzzlehttp/psr7`: Request Smuggling and Cache Poisoning via HTTP Header Injection

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist guzzlehttp/psr7
<2.10.2
2.10.2

Affected products

  • guzzle psr7

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-93 Improper Neutralization of CRLF Sequences
  • CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.