Описание
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.
Impact:
This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
A flaw was found in NGINX. An unauthenticated attacker can exploit this vulnerability by sending specially crafted HTTP requests when the map directive uses regular expression (regex) matching and references regex capture variables before referencing the map output variable. This can lead to a heap buffer overflow, which may allow for arbitrary code execution on systems where Address Space Layout Randomization (ASLR) is disabled or bypassed. Additionally, this flaw can cause a denial-of-service (DoS) due to the NGINX worker process restarting.
Отчет
This vulnerability in NGINX allows a remote, unauthenticated attacker to trigger a heap buffer overflow, leading to a denial of service (Dos). This occurs when the map directive uses regex matching and references regex capture variables before the map output variable. While arbitrary code execution is a theoretical risk, it is significantly reduced on Red Hat systems where Address Space Layout Randomization (ASLR) is enabled by default.
Меры по смягчению последствий
To mitigate this vulnerability, do not use unnamed captures. Use named captures instead and only use them in the same block with the regex match. Red Hat recommends updating nginx to the latest version when a fix is available.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Hardened Images | php | Not affected | ||
| Red Hat Lightspeed proxy 1 | insights-proxy/insights-proxy-container-rhel9 | Affected | ||
| Red Hat Enterprise Linux 10 | nginx | Fixed | RHSA-2026:67314 | 14.09.2026 |
| Red Hat Enterprise Linux 8 | nginx | Fixed | RHSA-2026:67315 | 14.09.2026 |
| Red Hat Enterprise Linux 9 | nginx | Fixed | RHSA-2026:66542 | 11.09.2026 |
| Red Hat Enterprise Linux 9 | nginx | Fixed | RHSA-2026:67283 | 14.09.2026 |
| Red Hat Enterprise Linux 9 | nginx | Fixed | RHSA-2026:67308 | 14.09.2026 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | nginx | Fixed | RHSA-2026:93472 | 02.11.2026 |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | nginx | Fixed | RHSA-2026:93468 | 02.11.2026 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | nginx | Fixed | RHSA-2026:93467 | 02.11.2026 |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Su...
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technica
A vulnerability exists in NGINX Plus and NGINX Open Source when a mapd ...
EPSS
7 High
CVSS3