CVE-2026-45123
- Source
- https://cve.org/CVERecord?id=CVE-2026-45123
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45123.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-45123
- Aliases
-
- GHSA-56wr-64wx-5g7j
- Published
- 2026-08-18T15:44:26Z
- Modified
- 2026-09-10T03:30:49Z
- Severity
-
- 4.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
- Summary
- MyBB: IPv6 SSRF
- Details
-
MyBB is free and open source forum software. Prior to 1.8.40, the remote requests feature does not correctly handle IPv6 addresses, resulting in a server-side request forgery vulnerability. The default disallowed remote hosts list does not include IPv6 addresses. Verification in fetch_remote_file() fails open when get_ip_by_hostname() returns no result because that function does not return IPv6 results, allowing a crafted remote target to bypass the host restriction. The uniquely identifying implementation details include fail-open verification, and inc/functions.php. This issue is fixed in version 1.8.40.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-918" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45123.json", "unresolved_ranges": [ { "extracted_events": [ { "fixed": "1.8.40" } ], "source": "AFFECTED_FIELD" } ] }- References
-
- https://github.com/mybb/mybb/releases/tag/mybb_1840
- https://mybb.com/versions/1.8.40
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45123.json
- https://github.com/mybb/mybb/security/advisories/GHSA-56wr-64wx-5g7j
- https://nvd.nist.gov/vuln/detail/CVE-2026-45123
- https://github.com/mybb/mybb/commit/9cdadbf66f4cef50019f13aaa8e3470ea6535cb7
Affected packages
Git / github.com/mybb/mybb
Affected versions
Other
mybb_1800
mybb_1801
mybb_1804
mybb_1805
mybb_1806
mybb_1807
mybb_1808
mybb_1809
mybb_1810
mybb_1811
mybb_1812
mybb_1813
mybb_1814
mybb_1815
mybb_1815_build
mybb_1816
mybb_1816_build
mybb_1817
mybb_1817_build
mybb_1818
mybb_1818_build
mybb_1819
mybb_1819_build
mybb_1820
mybb_1820-rc
mybb_1820_build
mybb_1821
mybb_1821_build
mybb_1821pl1
mybb_1822
mybb_1822_build
mybb_1823
mybb_1823_build
mybb_1827
mybb_1827_build
mybb_1828
mybb_1828_build
mybb_1829
mybb_1831
mybb_1831_build
mybb_1832
mybb_1832_build
mybb_1833
mybb_1833_build
mybb_1834
mybb_1834_build
mybb_1835
mybb_1835_build
mybb_1836
mybb_1837
mybb_1837_build
mybb_1838
mybb_1838_build
mybb_1839
mybb_1839_build
mybb_1840_build