1 These are problems known to exist at the time of this release. Feel free to
2 join in and help us correct one or more of these! Also be sure to check the
3 changelog of the current development status, as one or more of these problems
4 may have been fixed since this was written!
6 83. curl is unable to load non-default openssl engines, because openssl isn't
7 initialized properly. This seems to require OpenSSL_config() or
8 CONF_modules_load_file() to be used by libcurl but the first seems to not
9 work and we've gotten not reports from tests with the latter. Possibly we
10 need to discuss with OpenSSL developers how this is supposed to be done. We
11 need users with actual external openssl engines for testing to work on this.
12 http://curl.haxx.se/bug/view.cgi?id=1208
14 82. When building with the Windows Borland compiler, it fails because the
15 "tlib" tool doesn't support hyphens (minus signs) in file names and we have
17 http://curl.haxx.se/bug/view.cgi?id=1222
19 81. When using -J (with -O), automaticly resumed downloading together with "-C
20 -" fails. Without -J the same command line works! This happens because the
21 resume logic is worked out before the target file name (and thus its
22 pre-transfer size) has been figured out!
23 http://curl.haxx.se/bug/view.cgi?id=1169
25 80. Curl doesn't recognize certificates in DER format in keychain, but it
27 http://curl.haxx.se/bug/view.cgi?id=3439999
29 79. SMTP. When sending data to multiple recipients, curl will abort and return
30 failure if one of the recipients indicate failure (on the "RCPT TO"
31 command). Ordinary mail programs would proceed and still send to the ones
32 that can receive data. This is subject for change in the future.
33 http://curl.haxx.se/bug/view.cgi?id=3438362
35 78. curl and libcurl don't always signal the client properly when "sending"
36 zero bytes files - it makes for example the command line client not creating
37 any file at all. Like when using FTP.
38 http://curl.haxx.se/bug/view.cgi?id=3438362
40 77. CURLOPT_FORBID_REUSE on a handle prevents NTLM from working since it
41 "abuses" the underlying connection re-use system and if connections are
42 forced to close they break the NTLM support.
44 76. The SOCKET type in Win64 is 64 bits large (and thus so is curl_socket_t on
45 that platform), and long is only 32 bits. It makes it impossible for
46 curl_easy_getinfo() to return a socket properly with the CURLINFO_LASTSOCKET
47 option as for all other operating systems.
49 75. NTLM authentication involving unicode user name or password only works
50 properly if built with UNICODE defined together with the schannel/winssl
51 backend. The original problem was mentioned in:
52 http://curl.haxx.se/mail/lib-2009-10/0024.html
53 http://curl.haxx.se/bug/view.cgi?id=2944325
55 The schannel version verified to work as mentioned in
56 http://curl.haxx.se/mail/lib-2012-07/0073.html
58 73. if a connection is made to a FTP server but the server then just never
59 sends the 220 response or otherwise is dead slow, libcurl will not
60 acknowledge the connection timeout during that phase but only the "real"
61 timeout - which may surprise users as it is probably considered to be the
62 connect phase to most people. Brought up (and is being misunderstood) in:
63 http://curl.haxx.se/bug/view.cgi?id=2844077
65 72. "Pausing pipeline problems."
66 http://curl.haxx.se/mail/lib-2009-07/0214.html
68 70. Problem re-using easy handle after call to curl_multi_remove_handle
69 http://curl.haxx.se/mail/lib-2009-07/0249.html
71 68. "More questions about ares behavior".
72 http://curl.haxx.se/mail/lib-2009-08/0012.html
74 67. When creating multipart formposts. The file name part can be encoded with
75 something beyond ascii but currently libcurl will only pass in the verbatim
76 string the app provides. There are several browsers that already do this
77 encoding. The key seems to be the updated draft to RFC2231:
78 http://tools.ietf.org/html/draft-reschke-rfc2231-in-http-02
80 66. When using telnet, the time limitation options don't work.
81 http://curl.haxx.se/bug/view.cgi?id=2818950
83 65. When doing FTP over a socks proxy or CONNECT through HTTP proxy and the
84 multi interface is used, libcurl will fail if the (passive) TCP connection
85 for the data transfer isn't more or less instant as the code does not
86 properly wait for the connect to be confirmed. See test case 564 for a first
89 63. When CURLOPT_CONNECT_ONLY is used, the handle cannot reliably be re-used
90 for any further requests or transfers. The work-around is then to close that
91 handle with curl_easy_cleanup() and create a new. Some more details:
92 http://curl.haxx.se/mail/lib-2009-04/0300.html
94 61. If an upload using Expect: 100-continue receives an HTTP 417 response,
95 it ought to be automatically resent without the Expect:. A workaround is
96 for the client application to redo the transfer after disabling Expect:.
97 http://curl.haxx.se/mail/archive-2008-02/0043.html
99 60. libcurl closes the connection if an HTTP 401 reply is received while it
100 is waiting for the the 100-continue response.
101 http://curl.haxx.se/mail/lib-2008-08/0462.html
103 58. It seems sensible to be able to use CURLOPT_NOBODY and
104 CURLOPT_FAILONERROR with FTP to detect if a file exists or not, but it is
105 not working: http://curl.haxx.se/mail/lib-2008-07/0295.html
107 56. When libcurl sends CURLOPT_POSTQUOTE commands when connected to a SFTP
108 server using the multi interface, the commands are not being sent correctly
109 and instead the connection is "cancelled" (the operation is considered done)
110 prematurely. There is a half-baked (busy-looping) patch provided in the bug
111 report but it cannot be accepted as-is. See
112 http://curl.haxx.se/bug/view.cgi?id=2006544
114 55. libcurl fails to build with MIT Kerberos for Windows (KfW) due to KfW's
115 library header files exporting symbols/macros that should be kept private
116 to the KfW library. See ticket #5601 at http://krbdev.mit.edu/rt/
118 52. Gautam Kachroo's issue that identifies a problem with the multi interface
119 where a connection can be re-used without actually being properly
121 http://curl.haxx.se/mail/lib-2008-01/0277.html
123 49. If using --retry and the transfer timeouts (possibly due to using -m or
124 -y/-Y) the next attempt doesn't resume the transfer properly from what was
125 downloaded in the previous attempt but will truncate and restart at the
126 original position where it was at before the previous failed attempt. See
127 http://curl.haxx.se/mail/lib-2008-01/0080.html and Mandriva bug report
128 https://qa.mandriva.com/show_bug.cgi?id=22565
130 48. If a CONNECT response-headers are larger than BUFSIZE (16KB) when the
131 connection is meant to be kept alive (like for NTLM proxy auth), the
132 function will return prematurely and will confuse the rest of the HTTP
133 protocol code. This should be very rare.
135 43. There seems to be a problem when connecting to the Microsoft telnet server.
136 http://curl.haxx.se/bug/view.cgi?id=1720605
138 41. When doing an operation over FTP that requires the ACCT command (but not
139 when logging in), the operation will fail since libcurl doesn't detect this
140 and thus fails to issue the correct command:
141 http://curl.haxx.se/bug/view.cgi?id=1693337
143 39. Steffen Rumler's Race Condition in Curl_proxyCONNECT:
144 http://curl.haxx.se/mail/lib-2007-01/0045.html
146 38. Kumar Swamy Bhatt's problem in ftp/ssl "LIST" operation:
147 http://curl.haxx.se/mail/lib-2007-01/0103.html
149 35. Both SOCKS5 and SOCKS4 proxy connections are done blocking, which is very
150 bad when used with the multi interface.
152 34. The SOCKS4 connection codes don't properly acknowledge (connect) timeouts.
153 Also see #12. According to bug #1556528, even the SOCKS5 connect code does
154 not do it right: http://curl.haxx.se/bug/view.cgi?id=1556528,
156 31. "curl-config --libs" will include details set in LDFLAGS when configure is
157 run that might be needed only for building libcurl. Further, curl-config
158 --cflags suffers from the same effects with CFLAGS/CPPFLAGS.
160 30. You need to use -g to the command line tool in order to use RFC2732-style
161 IPv6 numerical addresses in URLs.
163 29. IPv6 URLs with zone ID is not nicely supported.
164 http://www.ietf.org/internet-drafts/draft-fenner-literal-zone-02.txt (expired)
165 specifies the use of a plus sign instead of a percent when specifying zone
166 IDs in URLs to get around the problem of percent signs being
167 special. According to the reporter, Firefox deals with the URL _with_ a
168 percent letter (which seems like a blatant URL spec violation).
169 libcurl supports zone IDs where the percent sign is URL-escaped (i.e. %25).
171 See http://curl.haxx.se/bug/view.cgi?id=1371118
173 26. NTLM authentication using SSPI (on Windows) when (lib)curl is running in
174 "system context" will make it use wrong(?) user name - at least when compared
175 to what winhttp does. See http://curl.haxx.se/bug/view.cgi?id=1281867
177 23. SOCKS-related problems:
178 B) libcurl doesn't support FTPS over a SOCKS proxy.
179 E) libcurl doesn't support active FTP over a SOCKS proxy
181 We probably have even more bugs and lack of features when a SOCKS proxy is
184 21. FTP ASCII transfers do not follow RFC959. They don't convert the data
185 accordingly (not for sending nor for receiving). RFC 959 section 3.1.1.1
186 clearly describes how this should be done:
188 The sender converts the data from an internal character representation to
189 the standard 8-bit NVT-ASCII representation (see the Telnet
190 specification). The receiver will convert the data from the standard
191 form to his own internal form.
193 Since 7.15.4 at least line endings are converted.
195 16. FTP URLs passed to curl may contain NUL (0x00) in the RFC 1738 <user>,
196 <password>, and <fpath> components, encoded as "%00". The problem is that
197 curl_unescape does not detect this, but instead returns a shortened C
198 string. From a strict FTP protocol standpoint, NUL is a valid character
199 within RFC 959 <string>, so the way to handle this correctly in curl would
200 be to use a data structure other than a plain C string, one that can handle
201 embedded NUL characters. From a practical standpoint, most FTP servers
202 would not meaningfully support NUL characters within RFC 959 <string>,
203 anyway (e.g., UNIX pathnames may not contain NUL).
205 14. Test case 165 might fail on a system which has libidn present, but with an
206 old iconv version (2.1.3 is a known bad version), since it doesn't recognize
207 the charset when named ISO8859-1. Changing the name to ISO-8859-1 makes the
208 test pass, but instead makes it fail on Solaris hosts that use its native
211 13. curl version 7.12.2 fails on AIX if compiled with --enable-ares.
212 The workaround is to combine --enable-ares with --disable-shared
214 12. When connecting to a SOCKS proxy, the (connect) timeout is not properly
215 acknowledged after the actual TCP connect (during the SOCKS "negotiate"
218 10. To get HTTP Negotiate authentication to work fine, you need to provide a
219 (fake) user name (this concerns both curl and the lib) because the code
220 wrongly only considers authentication if there's a user name provided.
221 http://curl.haxx.se/bug/view.cgi?id=1004841. How?
222 http://curl.haxx.se/mail/lib-2004-08/0182.html
224 8. Doing resumed upload over HTTP does not work with '-C -', because curl
225 doesn't do a HEAD first to get the initial size. This needs to be done
226 manually for HTTP PUT resume to work, and then '-C [index]'.
228 6. libcurl ignores empty path parts in FTP URLs, whereas RFC1738 states that
229 such parts should be sent to the server as 'CWD ' (without an argument).
230 The only exception to this rule, is that we knowingly break this if the
231 empty part is first in the path, as then we use the double slashes to
232 indicate that the user wants to reach the root dir (this exception SHALL
233 remain even when this bug is fixed).
235 5. libcurl doesn't treat the content-length of compressed data properly, as
236 it seems HTTP servers send the *uncompressed* length in that header and
237 libcurl thinks of it as the *compressed* length. Some explanations are here:
238 http://curl.haxx.se/mail/lib-2003-06/0146.html
240 2. If a HTTP server responds to a HEAD request and includes a body (thus
241 violating the RFC2616), curl won't wait to read the response but just stop
242 reading and return back. If a second request (let's assume a GET) is then
243 immediately made to the same server again, the connection will be re-used
244 fine of course, and the second request will be sent off but when the
245 response is to get read, the previous response-body is what curl will read
246 and havoc is what happens.
247 More details on this is found in this libcurl mailing list thread:
248 http://curl.haxx.se/mail/lib-2002-08/0000.html