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PERL5283DELTA(1) Perl Programmers Reference Guide PERL5283DELTA(1)
NAME
perl5283delta - what is new for perl v5.28.3
DESCRIPTION
This document describes differences between the 5.28.2 release and the
5.28.3 release.
If you are upgrading from an earlier release such as 5.28.1, first read
perl5282delta, which describes differences between 5.28.1 and 5.28.2.
Security
[CVE-2020-10543] Buffer overflow caused by a crafted regular expression
A signed "size_t" integer overflow in the storage space calculations
for nested regular expression quantifiers could cause a heap buffer
overflow in Perl's regular expression compiler that overwrites memory
allocated after the regular expression storage space with attacker
supplied data.
The target system needs a sufficient amount of memory to allocate
partial expansions of the nested quantifiers prior to the overflow
occurring. This requirement is unlikely to be met on 64-bit systems.
Discovered by: ManhND of The Tarantula Team, VinCSS (a member of
Vingroup).
[CVE-2020-10878] Integer overflow via malformed bytecode produced by a
crafted regular expression
Integer overflows in the calculation of offsets between instructions
for the regular expression engine could cause corruption of the
intermediate language state of a compiled regular expression. An
attacker could abuse this behaviour to insert instructions into the
compiled form of a Perl regular expression.
Discovered by: Hugo van der Sanden and Slaven Rezic.
[CVE-2020-12723] Buffer overflow caused by a crafted regular expression
Recursive calls to "S_study_chunk()" by Perl's regular expression
compiler to optimize the intermediate language representation of a
regular expression could cause corruption of the intermediate language
state of a compiled regular expression.
Discovered by: Sergey Aleynikov.
Additional Note
An application written in Perl would only be vulnerable to any of the
above flaws if it evaluates regular expressions supplied by the
attacker. Evaluating regular expressions in this fashion is known to
be dangerous since the regular expression engine does not protect
against denial of service attacks in this usage scenario.
Incompatible Changes
There are no changes intentionally incompatible with Perl 5.28.2. If
any exist, they are bugs, and we request that you submit a report. See
"Reporting Bugs" below.
Modules and Pragmata
Acknowledgements
Perl 5.28.3 represents approximately 13 months of development since
Perl 5.28.2 and contains approximately 3,100 lines of changes across 48
files from 16 authors.
Excluding auto-generated files, documentation and release tools, there
were approximately 1,700 lines of changes to 9 .pm, .t, .c and .h
files.
Perl continues to flourish into its fourth decade thanks to a vibrant
community of users and developers. The following people are known to
have contributed the improvements that became Perl 5.28.3:
Chris 'BinGOs' Williams, Dan Book, Hugo van der Sanden, James E Keenan,
John Lightsey, Karen Etheridge, Karl Williamson, Matthew Horsfall, Max
Maischein, Nicolas R., Renee Baecker, Sawyer X, Steve Hay, Tom Hukins,
Tony Cook, Zak B. Elep.
The list above is almost certainly incomplete as it is automatically
generated from version control history. In particular, it does not
include the names of the (very much appreciated) contributors who
reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN
modules included in Perl's core. We're grateful to the entire CPAN
community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors,
please see the AUTHORS file in the Perl source distribution.
Reporting Bugs
If you find what you think is a bug, you might check the perl bug
database at <https://github.com/Perl/perl5/issues>. There may also be
information at <https://www.perl.org/>, the Perl Home Page.
If you believe you have an unreported bug, please open an issue at
<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down
to a tiny but sufficient test case.
If the bug you are reporting has security implications which make it
inappropriate to send to a public issue tracker, then see "SECURITY
VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to
report the issue.
Give Thanks
If you wish to thank the Perl 5 Porters for the work we had done in
Perl 5, you can do so by running the "perlthanks" program:
perlthanks
This will send an email to the Perl 5 Porters list with your show of
thanks.
SEE ALSO
The Changes file for an explanation of how to view exhaustive details
on what changed.
The INSTALL file for how to build Perl.