CVE-2024-2756VulnerabilityPublished 29 Apr 2024Updated 4 Nov 2025

CVE-2024-2756: PHP · Improper Input Validation

Affects PHPSource CVE Database V5

Mentioned vulnerabilities

CVE-2022-31629

Not known to be exploited · 38% EPSS · CVSS 6.5 Medium · fixed in 8.4.0 : update PHP when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 38.1% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 8.4.0, 8.3.0, 8.2.0 +1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Apr 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade debian/php to 8.4.0, 8.3.0, 8.2.0 or 8.1.0.

Affected software

Product	Affected	Fixed in
Debiandebian/php`pkg:deb/debian/php`Other threats	Affected <8.1.0 <8.2.0 <8.3.0 <8.4.0	Fixed in 8.1.0 8.2.0 8.3.0 8.4.0

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

AI-suggested

1. 2. Conduct a thorough audit of all web applications using affected PHP versions to identify usage of __Host- and __Secure- cookies and verify correct handling and validation of cookie attributes. 3. Implement server-side validation to reject or sanitize cookies that do not conform to expected security attributes, preventing acceptance of insecure cookies masquerading as secure. 4. Use web application firewalls (WAFs) to detect and block suspicious cookie-setting attempts that exploit this vulnerability. 5. Educate developers and administrators about the importance of proper cookie attribute enforcement and the risks posed by this vulnerability. 6. 7. Employ Content Security Policy (CSP) and SameSite cookie attributes to reduce the risk of cross-site attacks that could facilitate exploitation. 8. Regularly review logs for unusual cookie-setting patterns or repeated failed attempts to exploit this vulnerability.

Description

Due to an incomplete fix to CVE-2022-31629 https://github.com/advisories/GHSA-c43m-486j-j32p , network and same-site attackers can set a standard insecure cookie in the victim's browser which is treated as a __Host- or __Secure- cookie by PHP applications.

Impact

For European organizations, the primary impact of CVE-2024-2756 is on the integrity of web application security controls relying on cookie attributes for session management and access control. Attackers can exploit this vulnerability to set insecure cookies that PHP treats as secure, potentially enabling session fixation, privilege escalation, or bypass of security policies enforced via cookies. This could lead to unauthorized actions performed under a victim's session or manipulation of user state. While confidentiality and availability are not directly affected, the integrity breach can facilitate further attacks or fraud. Organizations in sectors with high web application exposure, such as finance, e-commerce, government, and healthcare, face increased risk. The lack of known exploits reduces immediate threat but does not eliminate the risk of future exploitation. The vulnerability's presence in widely deployed PHP versions means many European websites and services could be affected, especially those that have not updated PHP or implemented additional cookie security measures.

Summary

CVE-2024-2756 is a vulnerability in the PHP language affecting versions 8.1.*, 8.2.*, and 8.3.*. It arises from an incomplete remediation of CVE-2022-31629, which involved improper input validation (CWE-20). The flaw allows attackers operating within the network or on the same site to set cookies that are insecure but are incorrectly accepted by PHP applications as __Host- or __Secure- cookies. These cookie prefixes are intended to enforce strict security policies: __Host- cookies must be set from a secure origin, have no Domain attribute, and use the Secure attribute; __Secure- cookies require the Secure attribute. By bypassing these checks, attackers can inject cookies that PHP treats as highly trusted, potentially enabling cookie poisoning or session fixation attacks. This compromises the integrity of cookie-based security mechanisms but does not directly expose confidential data or disrupt availability. Exploitation requires no privileges but does require user interaction, such as visiting a malicious site or interacting with a crafted request. No known exploits have been reported in the wild, and no official patches have been linked yet, indicating that remediation is pending. The vulnerability is scored 6.5 on the CVSS v3.1 scale, reflecting a medium severity level due to its impact on integrity and ease of exploitation without privileges. Organizations using affected PHP versions in web-facing applications should prioritize assessment and mitigation to prevent potential abuse.

CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 17:55 UTC

WeaknessesCWE-20

Technical details

References

Community reviews

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