Описание
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.
In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.
Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.
A flaw was found in YAML::Syck. An attacker could exploit a heap use-after-free vulnerability by providing a specially crafted YAML document that reuses an anchor name as an anchors-table key. This flaw causes the software to read freed heap memory, which may lead to information disclosure or denial of service.
Отчет
This Important heap use-after-free vulnerability in perl-YAML-Syck can be triggered by processing a specially crafted YAML document. The flaw, exploitable through the default YAML loading mechanism, may lead to information disclosure or a denial of service in applications handling untrusted YAML input.
Меры по смягчению последствий
To reduce the risk associated with this vulnerability, avoid processing untrusted YAML documents with applications that use perl-YAML-Syck. Restricting the source of YAML input to trusted origins is an operational control that can limit exposure.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | perl-YAML-Syck | Out of support scope | ||
| Red Hat Enterprise Linux 7 | perl-YAML-Syck | Out of support scope | ||
| Red Hat Enterprise Linux 8 | perl-YAML-Syck | Fix deferred |
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Дополнительная информация
Статус:
EPSS
6.3 Medium
CVSS3
Связанные уязвимости
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free v ...
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.
EPSS
6.3 Medium
CVSS3