Description
istream.c in w3m 0.5.2 and possibly other versions, when ssl_verify_server is enabled, does not properly handle a '\0' character in a domain name in the (1) subject's Common Name or (2) Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | w3m | 0.5.2-5 | — |
| Debian 13 | w3m | 0.5.2-5 | — |
| Debian 12 | w3m | 0.5.2-5 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | w3m +1 | 0.5.1-17.el5_5 | RHSA-2010:0565 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 11 SP4 | w3m | 0.5.3.git20161120-4.1 | SUSE-SU-2016:3046-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 11 SP4 | w3m | 0.5.3.git20161120-4.1 | SUSE-SU-2016:3046-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | w3m | 0.5.3.git20161120-1.1 | openSUSE-SU-2024:10235-1 |
Advisories 3
- RHSA-2010:0565 Red Hat Security Advisory: w3m security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- SUSE-SU-2016:3046-1 Security update for w3m SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10235-1 w3m-0.5.3.git20161120-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- [oss-security] 20100614 CVE Request: w3m does not check null bytes CN/subjAltName mailing-list
- 40134 third-party-advisory
- 65538 vdb-entry
- 1024252 vdb-entry
- ADV-2010-1467 vdb-entry
- ADV-2010-1879 vdb-entry
- ADV-2010-1928 vdb-entry
- SUSE-SR:2010:014 vendor-advisory
- RHSA-2010:0565 vendor-advisory
- 40837 vdb-entry
- 40733 third-party-advisory
- FEDORA-2010-10369 vendor-advisory