CVE-2026-63382

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)

• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)

• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)

• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)

• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)

• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)

• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)

• libevent: Libevent: Memory corruption due to use-after-free (CVE-2026-63381)

• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)

• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)

• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)

• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)

• libevent: Libevent: HTTP header smuggling allows authorization bypass or cache poisoning (CVE-2026-63379)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)

• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)

• libevent: Libevent: Memory corruption due to use-after-free (CVE-2026-63381)

• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)

• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)

• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)

• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)

• libevent: Libevent: HTTP header smuggling allows authorization bypass or cache poisoning (CVE-2026-63379)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)
• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)
• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)
• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)
• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)
• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)
• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)
• libevent: Libevent: Memory corruption due to use-after-free (CVE-2026-63381)
• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)
• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)
• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)
• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)
• libevent: Libevent: HTTP header smuggling allows authorization bypass or cache poisoning (CVE-2026-63379)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The libevent packages provide an abstract asynchronous event notification library.

Security Fix(es):

• libevent: Libevent: Denial of Service via malformed RPC data (CVE-2026-63383)
• libevent: Libevent: Off-by-one stack buffer overflow leading to denial of service or data corruption (CVE-2026-63387)
• libevent: Libevent: Memory corruption due to use-after-free (CVE-2026-63381)
• libevent: Libevent: Denial of Service via integer conversion error in evtag_unmarshal_header (CVE-2026-63384)
• libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling (CVE-2026-63382)
• libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling (CVE-2026-63388)
• libevent: Libevent: HTTP header handling bugs create risk of access control bypass. (CVE-2026-63385)
• libevent: Libevent: HTTP header smuggling allows authorization bypass or cache poisoning (CVE-2026-63379)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

• Fix CVE-2026-63381 - use-after-free in evbuffer_add_buffer_reference()
• Fix CVE-2026-63385 - HTTP header injection via CR/LF in header values
• Fix CVE-2026-63382 - HTTP request smuggling via Transfer-Encoding handling and bare-LF chunk framing
• Fix CVE-2026-63379 - HTTP header smuggling via chunked trailers

• CVE-2026-63383: fix out-of-bounds read in decode_tag_internal
• CVE-2026-63384: reject payload lengths above INT_MAX in evtag_unmarshal_header
• CVE-2026-63387: fix off-by-one stack buffer overflow in dnsname_to_labels
• CVE-2026-63385: reject HTTP header values containing CR or LF
• CVE-2026-63382: reject ambiguous Transfer-Encoding/Content-Length headers and require CRLF in chunked framing

• CVE-2026-63383: fix out-of-bounds read in decode_tag_internal
• CVE-2026-63384: reject payload lengths above INT_MAX in evtag_unmarshal_header
• CVE-2026-63387: fix off-by-one stack buffer overflow in dnsname_to_labels
• CVE-2026-63385: reject HTTP header values containing CR or LF
• CVE-2026-63382: reject ambiguous Transfer-Encoding/Content-Length headers and require CRLF in chunked framing

• CVE-2026-63383: fix out-of-bounds read in decode_tag_internal
• CVE-2026-63384: reject payload lengths above INT_MAX in evtag_unmarshal_header
• CVE-2026-63387: fix off-by-one stack buffer overflow in dnsname_to_labels
• CVE-2026-63385: reject HTTP header values containing CR or LF
• CVE-2026-63382: reject ambiguous Transfer-Encoding/Content-Length headers and require CRLF in chunked framing

• CVE-2026-63382: reject ambiguous Transfer-Encoding/Content-Length headers and require CRLF in chunked framing

The updated packages fix some security vulnerabilities.

These are all security issues fixed in the libevent-2_1-7-2.1.13-1.1 package on the GA media of openSUSE Tumbleweed.

Root has patched CVE-2026-63382 in the libevent package for Root:Debian:11. Multiple fixed versions available.

Root has patched CVE-2026-63382 in the libevent package for Root:Debian:12. Multiple fixed versions available.

Root has patched CVE-2026-63382 in the libevent package for Root:Debian:13. Multiple fixed versions available.

Alexis Challande discovered that libevent incorrectly handled certain empty output buffers. An attacker could possibly use this issue to trigger a use-after-free, resulting in a denial of service or arbitrary code execution. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-63381)

Rajat Raghav discovered that libevent incorrectly handled certain HTTP requests. An attacker could possibly use this issue to desynchronize HTTP request boundaries, resulting in HTTP request smuggling. (CVE-2026-63382)

Qiu Sihao discovered that libevent incorrectly handled certain malformed tagged RPC data. An attacker could possibly use this issue to trigger an out-of-bounds read, resulting in a denial of service. (CVE-2026-63383)

Qiu Sihao discovered that libevent incorrectly handled certain large payload lengths in tagged RPC data. An attacker could possibly use this issue to consume excessive system resources, resulting in a denial of service. (CVE-2026-63384)

Asaf Meizner discovered that libevent incorrectly handled certain HTTP URIs and header values. An attacker could possibly use this issue to cause HTTP messages to be interpreted inconsistently, resulting in security restrictions being bypassed. (CVE-2026-63385)