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 90. IMAP "SEARCH ALL" truncates output on large boxes. "A quick search of the
7 code reveals that pingpong.c contains some truncation code, at line 408,
8 when it deems the server response to be too large truncating it to 40
10 http://curl.haxx.se/bug/view.cgi?id=1366
12 89. Disabling HTTP Pipelining when there are ongoing transfers can lead to
13 heap corruption and crash. http://curl.haxx.se/bug/view.cgi?id=1411
15 88. libcurl doesn't support CURLINFO_FILETIME for SFTP transfers and thus
16 curl's -R option also doesn't work then.
18 87. -J/--remote-header-name doesn't decode %-encoded file names. RFC6266
19 details how it should be done. The can of worm is basically that we have no
20 charset handling in curl and ascii >=128 is a challenge for us. Not to
21 mention that decoding also means that we need to check for nastiness that is
22 attempted, like "../" sequences and the like. Probably everything to the left
23 of any embedded slashes should be cut off.
24 http://curl.haxx.se/bug/view.cgi?id=1294
26 86. The disconnect commands (LOGOUT and QUIT) may not be sent by IMAP, POP3
27 and SMTP if a failure occurs during the authentication phase of a
30 85. Wrong STARTTRANSFER timer accounting for POST requests
31 Timer works fine with GET requests, but while using POST the time for
32 CURLINFO_STARTTRANSFER_TIME is wrong. While using POST
33 CURLINFO_STARTTRANSFER_TIME minus CURLINFO_PRETRANSFER_TIME is near to zero
35 http://curl.haxx.se/bug/view.cgi?id=1213
37 84. CURLINFO_SSL_VERIFYRESULT is only implemented for the OpenSSL and NSS
38 backends, so relying on this information in a generic app is flaky.
40 82. When building with the Windows Borland compiler, it fails because the
41 "tlib" tool doesn't support hyphens (minus signs) in file names and we have
43 http://curl.haxx.se/bug/view.cgi?id=1222
45 81. When using -J (with -O), automatically resumed downloading together with
46 "-C -" fails. Without -J the same command line works! This happens because
47 the resume logic is worked out before the target file name (and thus its
48 pre-transfer size) has been figured out!
49 http://curl.haxx.se/bug/view.cgi?id=1169
51 80. Curl doesn't recognize certificates in DER format in keychain, but it
53 http://curl.haxx.se/bug/view.cgi?id=1065
55 79. SMTP. When sending data to multiple recipients, curl will abort and return
56 failure if one of the recipients indicate failure (on the "RCPT TO"
57 command). Ordinary mail programs would proceed and still send to the ones
58 that can receive data. This is subject for change in the future.
59 http://curl.haxx.se/bug/view.cgi?id=1116
61 78. curl and libcurl don't always signal the client properly when "sending"
62 zero bytes files - it makes for example the command line client not creating
63 any file at all. Like when using FTP.
64 http://curl.haxx.se/bug/view.cgi?id=1063
66 76. The SOCKET type in Win64 is 64 bits large (and thus so is curl_socket_t on
67 that platform), and long is only 32 bits. It makes it impossible for
68 curl_easy_getinfo() to return a socket properly with the CURLINFO_LASTSOCKET
69 option as for all other operating systems.
71 75. NTLM authentication involving unicode user name or password only works
72 properly if built with UNICODE defined together with the WinSSL/schannel
73 backend. The original problem was mentioned in:
74 http://curl.haxx.se/mail/lib-2009-10/0024.html
75 http://curl.haxx.se/bug/view.cgi?id=896
77 The WinSSL/schannel version verified to work as mentioned in
78 http://curl.haxx.se/mail/lib-2012-07/0073.html
80 73. if a connection is made to a FTP server but the server then just never
81 sends the 220 response or otherwise is dead slow, libcurl will not
82 acknowledge the connection timeout during that phase but only the "real"
83 timeout - which may surprise users as it is probably considered to be the
84 connect phase to most people. Brought up (and is being misunderstood) in:
85 http://curl.haxx.se/bug/view.cgi?id=856
87 72. "Pausing pipeline problems."
88 http://curl.haxx.se/mail/lib-2009-07/0214.html
90 70. Problem re-using easy handle after call to curl_multi_remove_handle
91 http://curl.haxx.se/mail/lib-2009-07/0249.html
93 68. "More questions about ares behavior".
94 http://curl.haxx.se/mail/lib-2009-08/0012.html
96 67. When creating multipart formposts. The file name part can be encoded with
97 something beyond ascii but currently libcurl will only pass in the verbatim
98 string the app provides. There are several browsers that already do this
99 encoding. The key seems to be the updated draft to RFC2231:
100 https://tools.ietf.org/html/draft-reschke-rfc2231-in-http-02
102 66. When using telnet, the time limitation options don't work.
103 http://curl.haxx.se/bug/view.cgi?id=846
105 65. When doing FTP over a socks proxy or CONNECT through HTTP proxy and the
106 multi interface is used, libcurl will fail if the (passive) TCP connection
107 for the data transfer isn't more or less instant as the code does not
108 properly wait for the connect to be confirmed. See test case 564 for a first
111 63. When CURLOPT_CONNECT_ONLY is used, the handle cannot reliably be re-used
112 for any further requests or transfers. The work-around is then to close that
113 handle with curl_easy_cleanup() and create a new. Some more details:
114 http://curl.haxx.se/mail/lib-2009-04/0300.html
116 61. If an upload using Expect: 100-continue receives an HTTP 417 response,
117 it ought to be automatically resent without the Expect:. A workaround is
118 for the client application to redo the transfer after disabling Expect:.
119 http://curl.haxx.se/mail/archive-2008-02/0043.html
121 60. libcurl closes the connection if an HTTP 401 reply is received while it
122 is waiting for the the 100-continue response.
123 http://curl.haxx.se/mail/lib-2008-08/0462.html
125 58. It seems sensible to be able to use CURLOPT_NOBODY and
126 CURLOPT_FAILONERROR with FTP to detect if a file exists or not, but it is
127 not working: http://curl.haxx.se/mail/lib-2008-07/0295.html
129 56. When libcurl sends CURLOPT_POSTQUOTE commands when connected to a SFTP
130 server using the multi interface, the commands are not being sent correctly
131 and instead the connection is "cancelled" (the operation is considered done)
132 prematurely. There is a half-baked (busy-looping) patch provided in the bug
133 report but it cannot be accepted as-is. See
134 http://curl.haxx.se/bug/view.cgi?id=748
136 55. libcurl fails to build with MIT Kerberos for Windows (KfW) due to KfW's
137 library header files exporting symbols/macros that should be kept private
138 to the KfW library. See ticket #5601 at http://krbdev.mit.edu/rt/
140 52. Gautam Kachroo's issue that identifies a problem with the multi interface
141 where a connection can be re-used without actually being properly
143 http://curl.haxx.se/mail/lib-2008-01/0277.html
145 49. If using --retry and the transfer timeouts (possibly due to using -m or
146 -y/-Y) the next attempt doesn't resume the transfer properly from what was
147 downloaded in the previous attempt but will truncate and restart at the
148 original position where it was at before the previous failed attempt. See
149 http://curl.haxx.se/mail/lib-2008-01/0080.html and Mandriva bug report
150 https://qa.mandriva.com/show_bug.cgi?id=22565
152 48. If a CONNECT response-headers are larger than BUFSIZE (16KB) when the
153 connection is meant to be kept alive (like for NTLM proxy auth), the
154 function will return prematurely and will confuse the rest of the HTTP
155 protocol code. This should be very rare.
157 43. There seems to be a problem when connecting to the Microsoft telnet server.
158 http://curl.haxx.se/bug/view.cgi?id=649
160 41. When doing an operation over FTP that requires the ACCT command (but not
161 when logging in), the operation will fail since libcurl doesn't detect this
162 and thus fails to issue the correct command:
163 http://curl.haxx.se/bug/view.cgi?id=635
165 39. Steffen Rumler's Race Condition in Curl_proxyCONNECT:
166 http://curl.haxx.se/mail/lib-2007-01/0045.html
168 38. Kumar Swamy Bhatt's problem in ftp/ssl "LIST" operation:
169 http://curl.haxx.se/mail/lib-2007-01/0103.html
171 35. Both SOCKS5 and SOCKS4 proxy connections are done blocking, which is very
172 bad when used with the multi interface.
174 34. The SOCKS4 connection codes don't properly acknowledge (connect) timeouts.
175 Also see #12. According to bug #1556528, even the SOCKS5 connect code does
176 not do it right: http://curl.haxx.se/bug/view.cgi?id=604
178 31. "curl-config --libs" will include details set in LDFLAGS when configure is
179 run that might be needed only for building libcurl. Further, curl-config
180 --cflags suffers from the same effects with CFLAGS/CPPFLAGS.
182 26. NTLM authentication using SSPI (on Windows) when (lib)curl is running in
183 "system context" will make it use wrong(?) user name - at least when compared
184 to what winhttp does. See http://curl.haxx.se/bug/view.cgi?id=535
186 23. SOCKS-related problems:
187 B) libcurl doesn't support FTPS over a SOCKS proxy.
188 E) libcurl doesn't support active FTP over a SOCKS proxy
190 We probably have even more bugs and lack of features when a SOCKS proxy is
193 21. FTP ASCII transfers do not follow RFC959. They don't convert the data
194 accordingly (not for sending nor for receiving). RFC 959 section 3.1.1.1
195 clearly describes how this should be done:
197 The sender converts the data from an internal character representation to
198 the standard 8-bit NVT-ASCII representation (see the Telnet
199 specification). The receiver will convert the data from the standard
200 form to his own internal form.
202 Since 7.15.4 at least line endings are converted.
204 16. FTP URLs passed to curl may contain NUL (0x00) in the RFC 1738 <user>,
205 <password>, and <fpath> components, encoded as "%00". The problem is that
206 curl_unescape does not detect this, but instead returns a shortened C
207 string. From a strict FTP protocol standpoint, NUL is a valid character
208 within RFC 959 <string>, so the way to handle this correctly in curl would
209 be to use a data structure other than a plain C string, one that can handle
210 embedded NUL characters. From a practical standpoint, most FTP servers
211 would not meaningfully support NUL characters within RFC 959 <string>,
212 anyway (e.g., Unix pathnames may not contain NUL).
214 14. Test case 165 might fail on a system which has libidn present, but with an
215 old iconv version (2.1.3 is a known bad version), since it doesn't recognize
216 the charset when named ISO8859-1. Changing the name to ISO-8859-1 makes the
217 test pass, but instead makes it fail on Solaris hosts that use its native
220 13. curl version 7.12.2 fails on AIX if compiled with --enable-ares.
221 The workaround is to combine --enable-ares with --disable-shared
223 12. When connecting to a SOCKS proxy, the (connect) timeout is not properly
224 acknowledged after the actual TCP connect (during the SOCKS "negotiate"
227 10. To get HTTP Negotiate (SPNEGO) authentication to work fine, you need to
228 provide a (fake) user name (this concerns both curl and the lib) because the
229 code wrongly only considers authentication if there's a user name provided.
230 http://curl.haxx.se/bug/view.cgi?id=440 How?
231 http://curl.haxx.se/mail/lib-2004-08/0182.html
233 8. Doing resumed upload over HTTP does not work with '-C -', because curl
234 doesn't do a HEAD first to get the initial size. This needs to be done
235 manually for HTTP PUT resume to work, and then '-C [index]'.
237 6. libcurl ignores empty path parts in FTP URLs, whereas RFC1738 states that
238 such parts should be sent to the server as 'CWD ' (without an argument).
239 The only exception to this rule, is that we knowingly break this if the
240 empty part is first in the path, as then we use the double slashes to
241 indicate that the user wants to reach the root dir (this exception SHALL
242 remain even when this bug is fixed).
244 5. libcurl doesn't treat the content-length of compressed data properly, as
245 it seems HTTP servers send the *uncompressed* length in that header and
246 libcurl thinks of it as the *compressed* length. Some explanations are here:
247 http://curl.haxx.se/mail/lib-2003-06/0146.html
249 2. If a HTTP server responds to a HEAD request and includes a body (thus
250 violating the RFC2616), curl won't wait to read the response but just stop
251 reading and return back. If a second request (let's assume a GET) is then
252 immediately made to the same server again, the connection will be re-used
253 fine of course, and the second request will be sent off but when the
254 response is to get read, the previous response-body is what curl will read
255 and havoc is what happens.
256 More details on this is found in this libcurl mailing list thread:
257 http://curl.haxx.se/mail/lib-2002-08/0000.html