PHP: Use After Free
CVE-2024-11235 is a high-severity use after free vulnerability in PHP from PHP Group, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.4.5, 8.3.19 as the first without the flaw, so updating PHP to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.48% chance of exploitation within 30 days, higher than 74% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update PHP to 8.4.5 or 8.3.19, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| PHP Group | PHP | 8.4.* up to, but not including, 8.4.5; 8.3.* up to, but not including, 8.3.19 | 8.4.5, 8.3.19 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.2 | Critical | CNA (php.net) |
| CVSS 3.1 | 8.1 | High | NVD |
Official description
In PHP versions 8.3.* before 8.3.19 and 8.4.* before 8.4.5, a code sequence involving __set handler or ??= operator and exceptions can lead to a use-after-free vulnerability. If the third party can control the memory layout leading to this, for example by supplying specially crafted inputs to the script, it could lead to remote code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in PHP
- 8.1 High severity
PHP Stale Internal Request-State Exploited
- 9.8 Critical severity
PHP Memory Corruption Exploited
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Use After Free vulnerabilities
- 8.6 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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