CVE-2021-21703
In PHP versions 7.3.x up to and including 7.3.31, 7.4.x below 7.4.25 and 8.0.x below 8.0.12, when running PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users, it is possible for the…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In PHP versions 7.3.x up to and including 7.3.31, 7.4.x below 7.4.25 and 8.0.x below 8.0.12, when running PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users, it is possible for the child processes to access memory shared with the main process and write to it, modifying it in a way that would cause the root process to conduct invalid memory reads and writes, which can be used to escalate privileges from local unprivileged user to the root user.
- CVSS 3.1
- 7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.44% probability · 72th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-284, CWE-787
- Affected
- php/php · debian/debian linux · fedoraproject/fedora · netapp/clustered data ontap · oracle/communications diameter signaling router
- Source
- security@php.net
References
- http://www.openwall.com/lists/oss-security/2021/10/26/7Mailing List, Patch, Third Party Advisory
- https://bugs.php.net/bug.php?id=81026Exploit, Issue Tracking, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/10/msg00021.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6PZVLICZUJMXOGWOUWSBAEGIVTF6Y6V3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JO5RA6YOBGGGKLIA6F6BQRZDDECF5L3R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PBM3KKB3RY2YPOKNMC4HIH7IH3T3WC74/
- https://security.gentoo.org/glsa/202209-20Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211118-0003/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4992Third Party Advisory
- https://www.debian.org/security/2021/dsa-4993Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Vendor Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2021/10/26/7Mailing List, Patch, Third Party Advisory
- https://bugs.php.net/bug.php?id=81026Exploit, Issue Tracking, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/10/msg00021.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6PZVLICZUJMXOGWOUWSBAEGIVTF6Y6V3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JO5RA6YOBGGGKLIA6F6BQRZDDECF5L3R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PBM3KKB3RY2YPOKNMC4HIH7IH3T3WC74/
- https://security.gentoo.org/glsa/202209-20Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211118-0003/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4992Third Party Advisory
- https://www.debian.org/security/2021/dsa-4993Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Vendor Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.