Assessment
Why it matters
EPSS is 0.5%; technical severity is CVSS 8.1.
Attacker-provided inputs to bccomp() could lead to an out-of-bounds write with stack and heap corruption in PHP versions from 8.4.* before 8.4.24 and from 8.5.* before 8.5.9.
Who should care
- Teams operating PHP
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether PHP is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Vendor advisory from github.com
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Verification noteAutomated link verification has not completed for this guidance yet.
Technical details
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:N/R:X/V:X/RE:X/U:X
- CWE
- CWE-787
- Affected versions
- PHP PHP (Start Including 8.4.0, End Excluding 8.4.24 | Start Including 8.5.0, End Excluding 8.5.9)
- Fixed versions
- PHP PHP (Fixed from 8.4.24, 8.5.9)
- Published
- 30 July 2026
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Latest EPSS score: 0.5%
- Signal calculated at 13