CVE-2017-8923
The zend_string_extend function in Zend/zend_string.h in PHP through 7.1.5 does not prevent changes to string objects that result in a negative length, which allows remote attackers to cause a denial of service (application crash) or possibly have…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (7.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The zend_string_extend function in Zend/zend_string.h in PHP through 7.1.5 does not prevent changes to string objects that result in a negative length, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact by leveraging a script's use of .= with a long string.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 7.19% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- php/php
- Source
- cve@mitre.org
EPSS 7.2% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/98518Third Party Advisory, VDB Entry
- https://bugs.php.net/bug.php?id=74577Exploit, Issue Tracking, Vendor Advisory
- http://www.securityfocus.com/bid/98518Third Party Advisory, VDB Entry
- https://bugs.php.net/bug.php?id=74577Exploit, Issue Tracking, Vendor Advisory
- https://security.netapp.com/advisory/ntap-20241227-0007/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.