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CVE-2023-38545

CRITICALCVSS 9.8/10EPSS 78.48%

Last modified

CVE-2023-38545 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.. EPSS estimates a 78.48% chance of exploitation in the next 30 days.

Description

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
78.48%

99.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
HaxxLibcurl>= 7.69.0, < 8.4.0
FedoraprojectFedora37
NetappActive Iq Unified ManagerAll versions
NetappOncommand InsightAll versions
NetappOncommand Workflow AutomationAll versions
MicrosoftWindows 10 1809< 10.0.17763.5122
MicrosoftWindows 10 21h2< 10.0.19044.3693
MicrosoftWindows 10 22h2< 10.0.19045.3693
MicrosoftWindows 11 21h2< 10.0.22000.2600
MicrosoftWindows 11 22h2< 10.0.22621.2715
MicrosoftWindows 11 23h2< 10.0.22631.2715
MicrosoftWindows Server 2019< 10.0.17763.5122
MicrosoftWindows Server 2022< 10.0.20348.2113

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2023-38545?
This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.
How severe is CVE-2023-38545?
CVE-2023-38545 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 78.48% probability of exploitation in the next 30 days.
How do I fix CVE-2023-38545?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST