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CVE-2026-63073

Опубликовано: 25 авг. 2026
Источник: redhat
CVSS3: 5.9
EPSS Низкий

Описание

Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to ERR_raise_data(). Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as "CN=%s%n" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses. Since the attacker controls the format string but none of the variadic arguments, such specifiers as %s and %n dereference or write through unrelated stack contents and crash the client. The reliable consequence is a denial of service, when the response comes from a malicious or intercepted CMP endpoint. There is no controlled memory write, arbitrary-address read, or reliable path to remote code execution. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.

A flaw was found in OpenSSL. A malicious CMP (Certificate Management Protocol) endpoint can send an unexpected distinguished name (DN) directly as the format string argument to ERR_raise_data(), causing the application to dereference and write to unrelated stack contents. This can lead to a crash in the CMP client, resulting in a denial of service.

Отчет

Applications acting as a CMP client connecting to a malicious or intercepted CMP server are vulnerable to this issue, limiting its exposure. Also, the CMP client needs to enforce an expected sender or use a pinned server certificate whose subject becomes the default expected sender. This flaw can cause the application to dereference and write to unrelated stack contents, leading to a crash in the CMP client and resulting in a denial of service. There is no controlled memory write, arbitrary-address read or path to code execution. For these reasons, this vulnerability has been rated with a low severity.

Меры по смягчению последствий

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Developer Hubrhdh/rhdh-hub-rhel9Fix deferred
Red Hat Enterprise Linux 10edk2Fix deferred
Red Hat Enterprise Linux 10opensslAffected
Red Hat Enterprise Linux 10shimNot affected
Red Hat Enterprise Linux 10shim-unsigned-aarch64Not affected
Red Hat Enterprise Linux 10shim-unsigned-x64Not affected
Red Hat Enterprise Linux 6opensslNot affected
Red Hat Enterprise Linux 7opensslNot affected
Red Hat Enterprise Linux 7ovmfNot affected
Red Hat Enterprise Linux 7shim-signedNot affected

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Дополнительная информация

Статус:

Low
Дефект:
CWE-134
https://bugzilla.redhat.com/show_bug.cgi?id=2517565openssl: untrusted sender DN used as format string in CMP response validation

EPSS

Процентиль: 58%
0.00929
Низкий

5.9 Medium

CVSS3

Связанные уязвимости

ubuntu
10 дней назад

Untrusted Sender DN Used as Format String in CMP Response Validation

nvd
10 дней назад

Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to `ERR_raise_data()`. Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as "CN=%s%n" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses.

debian
10 дней назад

Issue summary: OpenSSL CMP response validation passed an unexpected re ...

CVSS3: 9.8
github
10 дней назад

Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to `ERR_raise_data()`. Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as "CN=%s%n" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server respons...

EPSS

Процентиль: 58%
0.00929
Низкий

5.9 Medium

CVSS3