> CVE-2026-55766 [MEDIUM]

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PUBLISHED
2026-06-23 16:17
MODIFIED
2026-06-23 17:57
CVSS_SCORE V3
4.8
EPSS (Prob. Exploit)
0.23%
Top 86.2%
DATA SOURCES:
NVD 🔗 2026-06-23 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-11-01 GITHUB 🔗 2026-10-29 OSV 🔗 2026-11-02

> DESCRIPTION

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.1, guzzlehttp/psr7 did not reject CR/LF characters in certain first-party HTTP start-line fields: the request method, protocol version, and response reason phrase. If an application placed attacker-controlled data into one of those fields and later serialized the PSR-7 message as raw HTTP/1.x, for example with Message::toString() or an equivalent serializer, the serialized message could contain attacker-controlled header lines. The issue can also be reached through Message::parseRequest() or Message::parseResponse() when malformed raw messages are parsed into first-party PSR-7 objects and then serialized again. Creating or modifying a Request, Response, or other PSR-7 object alone is not sufficient. The issue requires the malformed message to be serialized and written to the network, forwarded, replayed, or otherwise processed by software that does not independently reject the malformed start line. This vulnerability is fixed in 2.12.1.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
EXPLOITABILITY
2.2
IMPACT
2.5

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
High (H)
Conditions spécifiques doivent être réunies pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
Low (L)
Divulgation limitée d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
Low
Divulgation limitée d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-93 CWE-113

> CWE DETAILED DESCRIPTIONS

CWE-93: Improper Neutralization of CRLF Sequences - The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. | CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers - The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.

> GITHUB SECURITY ADVISORY

GHSA-vm85-hxw5-5432 MODERATE

guzzlehttp/psr7: CRLF Injection in HTTP Start-Line Serialization

AFFECTED PACKAGES:
COMPOSER / guzzlehttp/psr7
< 2.12.1
Fixed in: 2.12.1

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

guzzlehttp/psr7: CRLF Injection in HTTP Start-Line Serialization

AFFECTED PACKAGES:
Unknown / Unknown
43 versions affected
ALIASES:
GHSA-vm85-hxw5-5432

> HISTORIQUE DES MODIFICATIONS

Première apparition
23/06/2026 16:17
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') - The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutr...
Nouvelle valeur:
CWE-93: Improper Neutralization of CRLF Sequences - The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectl...
📊 ENRICHISSEMENT 01/07/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') - The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutr...
Total des modifications: 2 Dernière mise à jour: 5 days ago

> REFERENCES

https://github.com/guzzle/psr7/security/advisories/GHSA-vm85-hxw5-5432
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