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Unrated severityNVD Advisory· Published Jun 8, 2026

CVE-2026-44631

CVE-2026-44631

Description

Apache HTTP Server 2.4.x versions prior to 2.4.68 are vulnerable to a buffer underwrite when processing crafted regular expressions in configuration.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Apache HTTP Server 2.4.x versions prior to 2.4.68 are vulnerable to a buffer underwrite when processing crafted regular expressions in configuration.

Vulnerability

A buffer underwrite vulnerability exists in Apache HTTP Server, specifically when processing crafted regular expressions within its configuration files. This issue affects versions from 2.4.0 through 2.4.67 [1].

Exploitation

An attacker can exploit this vulnerability by crafting specific regular expressions within the Apache HTTP Server configuration. The exact conditions or sequence of steps required to trigger the buffer underwrite are not detailed in the available references, but it is related to the processing of these regular expressions [1].

Impact

Successful exploitation of this buffer underwrite vulnerability could lead to a crash of the Apache HTTP Server process or potentially allow for arbitrary code execution, depending on the specific conditions and memory corruption achieved. The scope of impact would be limited to the server running the vulnerable Apache HTTP Server instance [1].

Mitigation

Users are recommended to upgrade to Apache HTTP Server version 2.4.68, which has been released and addresses this issue. This version was released on 2026-06-08 [1].

References
  1. Apache HTTP Server 2.4 vulnerabilities

AI Insight generated on Jun 8, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

1

Patches

1
35c6e405390e

cookie reqest header counting (#324)

https://github.com/icing/mod_h2Stefan EissingMay 27, 2026via body-scan
commit
1 file changed · +4 −0
  • mod_http2/h2_util.c+4 −0 modified
    @@ -1708,6 +1708,8 @@ static apr_status_t req_add_header(apr_table_t *headers, apr_pool_t *pool,
              && !ap_cstr_casecmpn("cookie", (const char *)nv->name, nv->namelen)) {
         existing = apr_table_get(headers, "cookie");
         if (existing) {
+            if (!nv->valuelen)
+                return APR_SUCCESS;
             /* Cookie header come separately in HTTP/2, but need
              * to be merged by "; " (instead of default ", ")
              */
@@ -1719,6 +1721,8 @@ static apr_status_t req_add_header(apr_table_t *headers, apr_pool_t *pool,
             apr_table_setn(headers, "Cookie",
                            apr_psprintf(pool, "%s; %.*s", existing,
                                         (int)nv->valuelen, nv->value));
+            /* Treat the merge as an "add" to not escape LimitRequestFields */
+            *pwas_added = 1;
             return APR_SUCCESS;
         }
     }

Vulnerability mechanics

No source-code context for this CVE — mechanics is only generated when we can read the actual fix diff. Without that, the four sections (root cause, attack vector, affected code, fix) would be speculation rather than analysis.

References

1

News mentions

1