Description
The idna_to_ascii_4i function in lib/idna.c in libidn before 1.33 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via 64 bytes of input.
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 | libidn | 1.33-1 | — |
| Debian 13 | libidn | 1.33-1 | — |
| Debian 12 | libidn | 1.33-1 | — |
| Debian 8 | libidn | 1.29-1+deb8u2 | DSA-3658-1 |
| Debian 7 | libidn | 1.25-2+deb7u2 | DLA-582-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | libidn | 1.32-3ubuntu1.1 | USN-3068-1 |
| Ubuntu 14.04 LTS | libidn | 1.28-1ubuntu2.1 | USN-3068-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | libidn | 1.28-4.1 | SUSE-SU-2016:2079-1 |
| SLES 11 SP4 | libidn | 1.10-6.1 | SUSE-SU-2016:2291-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | libidn | 1.28-4.1 | SUSE-SU-2016:2079-1 |
| SLES for SAP 11 SP4 | libidn | 1.10-6.1 | SUSE-SU-2016:2291-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | glibc | 2.34-1.2 | openSUSE-SU-2024:10792-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libidn | 1.33-r0 | — |
| Alpine v3.23 | libidn | 1.33-r0 | — |
| Alpine v3.22 | libidn | 1.33-r0 | — |
| Alpine v3.21 | libidn | 1.33-r0 | — |
| Alpine v3.20 | libidn | 1.33-r0 | — |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libidn | 1.33-r0 | — |
| Alpine v3.18 | libidn | 1.33-r0 | — |
| Alpine v3.17 | libidn | 1.33-r0 | — |
| Alpine v3.16 | libidn | 1.33-r0 | — |
| Alpine v3.15 | libidn | 1.33-r0 | — |
| Alpine v3.14 | libidn | 1.33-r0 | — |
| Alpine v3.13 | libidn | 1.33-r0 | — |
| Alpine v3.12 | libidn | 1.33-r0 | — |
| Alpine v3.11 | libidn | 1.33-r0 | — |
| Alpine v3.10 | libidn | 1.33-r0 | — |
| Alpine v3.9 | libidn | 1.33-r0 | — |
| Alpine v3.8 | libidn | 1.33-r0 | — |
| Alpine v3.7 | libidn | 1.33-r0 | — |
| Alpine v3.6 | libidn | 1.33-r0 | — |
| Alpine v3.5 | libidn | 1.33-r0 | — |
| Alpine v3.4 | libidn | 1.33-r0 | — |
| Alpine v3.3 | libidn | 1.33-r0 | — |
| Alpine v3.2 | libidn | 1.33-r0 | — |
Advisories 6
- USN-3068-1 libidn vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-582-1 libidn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3658-1 libidn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:2291-1 Security update for libidn SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10792-1 glibc-2.34-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2079-1 Security update for libidn SUSE / openSUSE Security Updates · Feb 4, 2026
References
- [oss-security] 20160721 Re: CVE request: multiple issues fixed in GNU libidn 1.33 mailing-list
- openSUSE-SU-2016:2135 vendor-advisory
- [oss-security] 20160720 CVE request: multiple issues fixed in GNU libidn 1.33 mailing-list
- 92070 vdb-entry
- DSA-3658 vendor-advisory
- http://git.savannah.gnu.org/cgit/libidn.git/commit/?id=f20ce1128fb7f4d33297eee307dddaf0f92ac72d
- [help-libidn] 20160720 Libidn 1.33 released mailing-list
- USN-3068-1 vendor-advisory
- [help-libidn] 20150709 out of bounds stack read in function idna_to_ascii_4i mailing-list
- [bookkeeper-issues] 20210628 [GitHub] [bookkeeper] padma81 opened a new issue #2746: Security Vulnerabilities in CentOS 7 image, Upgrade image to CentOS 8 mailing-list
- [bookkeeper-issues] 20210629 [GitHub] [bookkeeper] padma81 opened a new issue #2746: Security Vulnerabilities in CentOS 7 image, Upgrade image to CentOS 8 mailing-list