Denial of Service via crafted DNS responses
Summary
mtr is vulnerable to Out-of-bound read vulnerability in ipinfo_lookup() function. An attacker who can influence the TXT response used for AS lookups can trigger this bug by returning a DNS response that is larger than 512 bytes and uses a crafted compression pointer in the answer NAME field. ipinfo_lookup() function uses the length of the response as the end-of-message boundary for dn_expand() function. The result is a reliable crash. This issue exists in the mtr through version 0.96 and it was fixed in commit 48e1794414d338ce47abc0f27c25ade8788af9c3. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H). Weakness: CWE-823. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE.
What this means
In plain English
mtr is vulnerable to Out-of-bound read vulnerability in ipinfo_lookup() function. An attacker who can influence the TXT response used for AS lookups can trigger this bug by returning a DNS response that is larger than 512 bytes and uses a crafted compression pointer in the answer NAME field. ipinfo_lookup() function uses the length of the response as the end-of-message boundary for dn_expand() function. The result is a reliable crash. This issue exists in the mtr through version 0.96 and it was fixed in commit 48e1794414d338ce47abc0f27c25ade8788af9c3. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H). Successful exploitation can interrupt the affected service or exhaust resources, reducing availability until the component recovers.
Recommended action
Primary action: update to a vendor-listed fixed release: 0.96.
Rewritten locally from the scraped official advisory data above; no generative API is used. The vendor advisory is authoritative.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 0.96. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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