#VU47647 Out-of-bounds write in Oniguruma - CVE-2020-26159

Vulnerability identifier: #VU47647

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2020-26159

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Oniguruma
Universal components / Libraries / Libraries used by multiple products

Vendor: K.Kosako

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

In Oniguruma 6.9.5_rev1, an attacker able to supply a regular expression for compilation may be able to overflow a buffer by one byte in concat_opt_exact_str in src/regcomp.c .

Mitigation
Install update from vendor's website.

Vulnerable software versions

Oniguruma: 6.9.5

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External links
http://www.openwall.com/lists/oss-security/2020/09/30/7
http://github.com/kkos/oniguruma/commit/cbe9f8bd9cfc6c3c87a60fbae58fa1a85db59df0
http://github.com/kkos/oniguruma/issues/207
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2ZCUPCKJNSUHQMXXZBRNDDGQQLBJ2ACT/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4NHVR7X5ZLXUGW3PBCPQMNFQ3OJCSMQD/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZFUJY7BUIFBTZ3IUHVHCID4JYCRDGKPS/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.