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authorMiss Islington (bot) <31488909+miss-islington@users.noreply.github.com>2021-05-06 10:00:07 -0700
committerGitHub <noreply@github.com>2021-05-06 13:00:07 -0400
commit3fbe96123aeb66664fa547a8f6022efa2dc8788f (patch)
treef9964f2b3247079cc4040b5d13ebf27624022805
parent6c472d3a1d334d4eeb4a25eba7bf3b01611bf667 (diff)
downloadcpython-git-3fbe96123aeb66664fa547a8f6022efa2dc8788f.tar.gz
bpo-43075: Fix ReDoS in urllib AbstractBasicAuthHandler (GH-24391) (GH-25250)
Fix Regular Expression Denial of Service (ReDoS) vulnerability in urllib.request.AbstractBasicAuthHandler. The ReDoS-vulnerable regex has quadratic worst-case complexity and it allows cause a denial of service when identifying crafted invalid RFCs. This ReDoS issue is on the client side and needs remote attackers to control the HTTP server. (cherry picked from commit 7215d1ae25525c92b026166f9d5cac85fb1defe1) Co-authored-by: Yeting Li <liyt@ios.ac.cn>
-rw-r--r--Lib/urllib/request.py2
-rw-r--r--Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst1
2 files changed, 2 insertions, 1 deletions
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index 6624e04317..56565405a7 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -947,7 +947,7 @@ class AbstractBasicAuthHandler:
# (single quotes are a violation of the RFC, but appear in the wild)
rx = re.compile('(?:^|,)' # start of the string or ','
'[ \t]*' # optional whitespaces
- '([^ \t]+)' # scheme like "Basic"
+ '([^ \t,]+)' # scheme like "Basic"
'[ \t]+' # mandatory whitespaces
# realm=xxx
# realm='xxx'
diff --git a/Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst b/Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst
new file mode 100644
index 0000000000..1c9f727e96
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst
@@ -0,0 +1 @@
+Fix Regular Expression Denial of Service (ReDoS) vulnerability in :class:`urllib.request.AbstractBasicAuthHandler`. The ReDoS-vulnerable regex has quadratic worst-case complexity and it allows cause a denial of service when identifying crafted invalid RFCs. This ReDoS issue is on the client side and needs remote attackers to control the HTTP server.