UnratedFix available
nginx: Fix of CVE-2026-9256
Type: advisorySources: OSV
- CVE-2026-9256: heap buffer overflow in ngx_http_script_regex_start_code() when a rewrite replacement contains overlapping captures with the redirect parameter or argument string; the per-capture length accumulation is refactored to also account for escape-uri expansion per capture region, preventing under-allocation of the rewrite output buffer
- Products
- nginx, nginx-all-modules, nginx-core, nginx-filesystem, nginx-mod-devel, nginx-mod-http-image-filter, nginx-mod-http-perl, nginx-mod-http-xslt-filter, nginx-mod-mail, nginx-mod-stream
- Affected versions
- Not specified
- Fixed versions
- 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
- CVEs
- CVE-2026-9256
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 10:37 UTC · Revision 1
Source evidence
- CVE-2026-9256: heap buffer overflow in ngx_http_script_regex_start_code() when a rewrite replacement contains overlapping captures with the redirect parameter or argument string; the per-capture length accumulation is refactored to also account for escape-uri expansion per capture region, preventing under-allocation of the rewrite output buffer
osv:CLSA-2026-1779712426
nginx
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-all-modules
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-core
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-filesystem
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-devel
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-http-image-filter
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-http-perl
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-http-xslt-filter
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-mail
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
nginx-mod-stream
Fixed versions: 1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9
Complete source record
{
"id": "a70c600cff9f0dcdf46cfe7f8698be374548880f389ead0f89ae60e68c505149",
"url": "https://osv.dev/vulnerability/CLSA-2026-1779712426",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "nginx: Fix of CVE-2026-9256",
"summary": "- CVE-2026-9256: heap buffer overflow in ngx_http_script_regex_start_code() when a rewrite replacement contains overlapping captures with the redirect parameter or argument string; the per-capture length accumulation is refactored to also account for escape-uri expansion per capture region, preventing under-allocation of the rewrite output buffer",
"evidence": "osv:CLSA-2026-1779712426",
"products": [
{
"name": {
"value": "nginx",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-all-modules",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-core",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-filesystem",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-devel",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-http-image-filter",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-http-perl",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/6/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-http-xslt-filter",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/7/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-mail",
"evidence": "/affected/8/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/8/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "nginx-mod-stream",
"evidence": "/affected/9/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9",
"evidence": "/affected/9/ranges"
}
],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "CLSA-2026-1779712426",
"aliases": [
"CLSA-2026-1779712426"
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx",
"purl": "pkg:rpm/tuxcare/nginx?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-all-modules",
"purl": "pkg:rpm/tuxcare/nginx-all-modules?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-core",
"purl": "pkg:rpm/tuxcare/nginx-core?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-filesystem",
"purl": "pkg:rpm/tuxcare/nginx-filesystem?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-devel",
"purl": "pkg:rpm/tuxcare/nginx-mod-devel?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-http-image-filter",
"purl": "pkg:rpm/tuxcare/nginx-mod-http-image-filter?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-http-perl",
"purl": "pkg:rpm/tuxcare/nginx-mod-http-perl?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-http-xslt-filter",
"purl": "pkg:rpm/tuxcare/nginx-mod-http-xslt-filter?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-mail",
"purl": "pkg:rpm/tuxcare/nginx-mod-mail?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.20.1-14.el9_2.1.alma.1.tuxcare.els9"
}
]
}
],
"package": {
"name": "nginx-mod-stream",
"purl": "pkg:rpm/tuxcare/nginx-mod-stream?distro=almalinux-9.2",
"ecosystem": "TuxCare:AlmaLinux:9.2"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/almalinux9.2esu/CLSA-2026-1779712426.json"
}
}
],
"modified": "2026-10-26T09:30:02.914057884Z",
"provider": "osv",
"upstream": [
"CVE-2026-9256"
],
"references": [
"https://errata.tuxcare.com/els_os/almalinux9.2esu/CLSA-2026-1779712426.html"
]
},
"related_cves": [
{
"value": "CVE-2026-9256",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 446820,
"published_at": "2026-05-25T12:33:51+00:00"
}