When curl is asked to use HSTS, the expiry time for a subdomain might
overwrite a parent domain's cache entry, making it end sooner or later than
otherwise intended.
This affects curl using applications that enable HSTS and use URLs with the
insecure `HTTP://` scheme and perform transfers with hosts like
`x.example.com` as well as `example.com` where the first host is a subdomain
of the second host.
(The HSTS cache either needs to have been populated manually or there needs to
have been previous HTTPS accesses done as the cache needs to have entries for
the domains involved to trigger this problem.)
When `x.example.com` responds with `Strict-Transport-Security:` headers, this
bug can make the subdomain's expiry timeout *bleed over* and get set for the
parent domain `example.com` in curl's HSTS cache.
The result of a triggered bug is that HTTP accesses to `example.com` get
converted to HTTPS for a different period of time than what was asked for by
the origin server. If `example.com` for example stops supporting HTTPS at its
expiry time, curl might then fail to access `http://example.com` until the
(wrongly set) timeout expires. This bug can also expire the parent's entry
*earlier*, thus making curl inadvertently switch back to insecure HTTP earlier
than otherwise intended.
CVSS Score
6.5
EPSS Score
0.002
Published
2024-11-06
curl inadvertently kept the SSL session ID for connections in its cache even when the verify status (*OCSP stapling*) test failed. A subsequent transfer to
the same hostname could then succeed if the session ID cache was still fresh, which then skipped the verify status check.
CVSS Score
5.3
EPSS Score
0.002
Published
2024-02-03
When saving HSTS data to an excessively long file name, curl could end up
removing all contents, making subsequent requests using that file unaware of
the HSTS status they should otherwise use.
CVSS Score
5.3
EPSS Score
0.002
Published
2023-12-12
This flaw allows a malicious HTTP server to set "super cookies" in curl that
are then passed back to more origins than what is otherwise allowed or
possible. This allows a site to set cookies that then would get sent to
different and unrelated sites and domains.
It could do this by exploiting a mixed case flaw in curl's function that
verifies a given cookie domain against the Public Suffix List (PSL). For
example a cookie could be set with `domain=co.UK` when the URL used a lower
case hostname `curl.co.uk`, even though `co.uk` is listed as a PSL domain.
CVSS Score
6.5
EPSS Score
0.003
Published
2023-12-07
When curl retrieves an HTTP response, it stores the incoming headers so that
they can be accessed later via the libcurl headers API.
However, curl did not have a limit in how many or how large headers it would
accept in a response, allowing a malicious server to stream an endless series
of headers and eventually cause curl to run out of heap memory.
CVSS Score
7.5
EPSS Score
0.145
Published
2023-09-15
Integer overflow vulnerability in tool_operate.c in curl 7.65.2 via a large value as the retry delay. NOTE: many parties report that this has no direct security impact on the curl user; however, it may (in theory) cause a denial of service to associated systems or networks if, for example, --retry-delay is misinterpreted as a value much smaller than what was intended. This is not especially plausible because the overflow only happens if the user was trying to specify that curl should wait weeks (or longer) before trying to recover from a transient error.
CVSS Score
3.3
EPSS Score
0.0
Published
2023-08-22
An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS library. This private wildcard matching function would match IDN (International Domain Name) hosts incorrectly and could as a result accept patterns that otherwise should mismatch. IDN hostnames are converted to puny code before used for certificate checks. Puny coded names always start with `xn--` and should not be allowed to pattern match, but the wildcard check in curl could still check for `x*`, which would match even though the IDN name most likely contained nothing even resembling an `x`.
CVSS Score
5.9
EPSS Score
0.003
Published
2023-05-26
An information disclosure vulnerability exists in curl <v8.1.0 when doing HTTP(S) transfers, libcurl might erroneously use the read callback (`CURLOPT_READFUNCTION`) to ask for data to send, even when the `CURLOPT_POSTFIELDS` option has been set, if the same handle previously wasused to issue a `PUT` request which used that callback. This flaw may surprise the application and cause it to misbehave and either send off the wrong data or use memory after free or similar in the second transfer. The problem exists in the logic for a reused handle when it is (expected to be) changed from a PUT to a POST.
CVSS Score
3.7
EPSS Score
0.005
Published
2023-05-26
A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.
CVSS Score
5.9
EPSS Score
0.006
Published
2023-05-26
A use after free vulnerability exists in curl <v8.1.0 in the way libcurl offers a feature to verify an SSH server's public key using a SHA 256 hash. When this check fails, libcurl would free the memory for the fingerprint before it returns an error message containing the (now freed) hash. This flaw risks inserting sensitive heap-based data into the error message that might be shown to users or otherwise get leaked and revealed.
CVSS Score
7.5
EPSS Score
0.003
Published
2023-05-26
Page 1