From 3c92a9dd3ad51f55a886cd67250458cd6350c366 Mon Sep 17 00:00:00 2001 From: Hetvi Thakar Date: Thu, 15 Oct 2026 20:20:47 -0700 Subject: [PATCH] nginx: fix CVE-2026-42934 This patch applies the upstream fix as referenced in [2], using the commit shown in [1]. [1] https://github.com/nginx/nginx/commit/54b7945961b2eaafc480d6b85d9635d0db1c126a [2] https://nginx.org/en/security_advisories.html Signed-off-by: Hetvi Thakar Signed-off-by: Anuj Mittal --- .../nginx/files/CVE-2026-42934.patch | 80 +++++++++++++++++++ .../recipes-httpd/nginx/nginx_1.28.3.bb | 1 + .../recipes-httpd/nginx/nginx_1.29.7.bb | 1 + 3 files changed, 82 insertions(+) create mode 100644 meta-webserver/recipes-httpd/nginx/files/CVE-2026-42934.patch diff --git a/meta-webserver/recipes-httpd/nginx/files/CVE-2026-42934.patch b/meta-webserver/recipes-httpd/nginx/files/CVE-2026-42934.patch new file mode 100644 index 0000000000..5ae96e8372 --- /dev/null +++ b/meta-webserver/recipes-httpd/nginx/files/CVE-2026-42934.patch @@ -0,0 +1,80 @@ +From 54b7945961b2eaafc480d6b85d9635d0db1c126a Mon Sep 17 00:00:00 2001 +From: David Carlier +Date: Sun, 12 Apr 2026 07:13:23 +0100 +Subject: [PATCH] Charset: fix buffer over-read in recode_from_utf8(). + +When a multi-byte UTF-8 character was split across 3+ single-byte +buffers, the saved bytes continuation path had two related bugs: + +ngx_utf8_decode() was called with the last saved-array index instead +of the byte count, causing it to report "incomplete" even when the +sequence was already complete. + +The subsequent ngx_memcpy() used that same index as the copy length, +reading past the input buffer boundary. + +CVE: CVE-2026-42934 +Upstream-Status: Backport [https://github.com/nginx/nginx/commit/54b7945961b2eaafc480d6b85d9635d0db1c126a] + +(cherry picked from commit 54b7945961b2eaafc480d6b85d9635d0db1c126a) +Signed-off-by: Hetvi Thakar +--- + .../modules/ngx_http_charset_filter_module.c | 20 ++++++------------- + 1 file changed, 6 insertions(+), 14 deletions(-) + +diff --git a/src/http/modules/ngx_http_charset_filter_module.c b/src/http/modules/ngx_http_charset_filter_module.c +index 482960040..edb2db568 100644 +--- a/src/http/modules/ngx_http_charset_filter_module.c ++++ b/src/http/modules/ngx_http_charset_filter_module.c +@@ -689,7 +689,6 @@ ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf, + u_char c, *p, *src, *dst, *saved, **table; + uint32_t n; + ngx_buf_t *b; +- ngx_uint_t i; + ngx_chain_t *out, *cl, **ll; + + src = buf->pos; +@@ -783,18 +782,12 @@ ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf, + ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pool->log, 0, + "http charset utf saved: %z", ctx->saved_len); + +- p = src; +- +- for (i = ctx->saved_len; i < NGX_UTF_LEN; i++) { +- ctx->saved[i] = *p++; +- +- if (p == buf->last) { +- break; +- } +- } ++ len = ngx_min(NGX_UTF_LEN - ctx->saved_len, (size_t) (buf->last - src)); ++ ngx_memcpy(&ctx->saved[ctx->saved_len], src, len); ++ len += ctx->saved_len; + + saved = ctx->saved; +- n = ngx_utf8_decode(&saved, i); ++ n = ngx_utf8_decode(&saved, len); + + c = '\0'; + +@@ -810,7 +803,7 @@ ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf, + + /* incomplete UTF-8 symbol */ + +- if (i < NGX_UTF_LEN) { ++ if (len < NGX_UTF_LEN) { + out = ngx_http_charset_get_buf(pool, ctx); + if (out == NULL) { + return NULL; +@@ -823,8 +816,7 @@ ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf, + b->sync = 1; + b->shadow = buf; + +- ngx_memcpy(&ctx->saved[ctx->saved_len], src, i); +- ctx->saved_len += i; ++ ctx->saved_len = len; + + return out; + } +-- +2.35.6 diff --git a/meta-webserver/recipes-httpd/nginx/nginx_1.28.3.bb b/meta-webserver/recipes-httpd/nginx/nginx_1.28.3.bb index 25493be747..25d8784c48 100644 --- a/meta-webserver/recipes-httpd/nginx/nginx_1.28.3.bb +++ b/meta-webserver/recipes-httpd/nginx/nginx_1.28.3.bb @@ -2,6 +2,7 @@ require nginx.inc SRC_URI:append = " \ file://CVE-2026-40701.patch \ + file://CVE-2026-42934.patch \ " LIC_FILES_CHKSUM = "file://LICENSE;md5=3dc49537b08b14c8b66ad247bb4c4593" diff --git a/meta-webserver/recipes-httpd/nginx/nginx_1.29.7.bb b/meta-webserver/recipes-httpd/nginx/nginx_1.29.7.bb index c8881a320e..ae7bfaee9f 100644 --- a/meta-webserver/recipes-httpd/nginx/nginx_1.29.7.bb +++ b/meta-webserver/recipes-httpd/nginx/nginx_1.29.7.bb @@ -2,6 +2,7 @@ require nginx.inc SRC_URI:append = " \ file://CVE-2026-40701.patch \ + file://CVE-2026-42934.patch \ " # 1.28.x branch is the current stable branch, the recommended default