Description
The s_mp_div function in lib/freebl/mpi/mpi.c in Mozilla Network Security Services (NSS) before 3.21, as used in Mozilla Firefox before 44.0, improperly divides numbers, which might make it easier for remote attackers to defeat cryptographic protection mechanisms by leveraging use of the (1) mp_div or (2) mp_exptmod function.
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 | nss | 2:3.21-1 | — |
| Debian 13 | nss | 2:3.21-1 | — |
| Debian 12 | nss | 2:3.21-1 | — |
| Debian 8 | nss | 2:3.26-1+debu8u1 | DSA-3688-1 |
| Debian 7 | nss | 2:3.14.5-1+deb7u6 | DLA-480-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | nss | 3.12.8-1+squeeze14 | DLA-427-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | thunderbird | 1:38.8.0+build1-0ubuntu0.16.04.1 | USN-2973-1 |
| Ubuntu 14.04 LTS | firefox | 44.0+build3-0ubuntu0.14.04.1 | USN-2880-1 |
| Ubuntu 14.04 LTS | nss | 2:3.21-0ubuntu0.14.04.1 | USN-2903-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:38.8.0+build1-0ubuntu0.14.04.1 | USN-2973-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | MozillaFirefox | 38.6.0esr-57.3 | SUSE-SU-2016:0338-1 |
| SLES 12 SP1 | MozillaFirefox-branding-SLE | 31.0-20.1 | SUSE-SU-2016:0338-1 |
| SLES 12 SP1 | mozilla-nss | 3.20.2-37.1 | SUSE-SU-2016:0338-1 |
| SLES 12 | MozillaFirefox | 38.6.0esr-57.3 | SUSE-SU-2016:0338-1 |
| SLES 12 | MozillaFirefox-branding-SLE | 31.0-20.1 | SUSE-SU-2016:0338-1 |
| SLES 12 | mozilla-nss | 3.20.2-37.1 | SUSE-SU-2016:0338-1 |
| SLES 11 SP4 | MozillaFirefox | 38.6.0esr-31.3 | SUSE-SU-2016:0334-1 |
| SLES 11 SP4 | MozillaFirefox-branding-SLED | 38-18.24 | SUSE-SU-2016:0334-1 |
| SLES 11 SP4 | mozilla-nss | 3.20.2-25.2 | SUSE-SU-2016:0334-1 |
| SLES 11 SP3 | MozillaFirefox | 38.6.0esr-31.3 | SUSE-SU-2016:0334-1 |
| SLES 11 SP3 | MozillaFirefox-branding-SLED | 38-18.24 | SUSE-SU-2016:0334-1 |
| SLES 11 SP3 | mozilla-nss | 3.20.2-25.2 | SUSE-SU-2016:0334-1 |
| SLES 11 SP2 | MozillaFirefox | 38.6.1esr-33.1 | SUSE-SU-2016:0584-1 |
| SLES 11 SP2 | MozillaFirefox-branding-SLED | 38-15.58 | SUSE-SU-2016:0584-1 |
| SLES 11 SP2 | mozilla-nss | 3.20.2-17.5 | SUSE-SU-2016:0584-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | MozillaFirefox | 38.6.0esr-57.3 | SUSE-SU-2016:0338-1 |
| SLES for SAP 12 SP1 | MozillaFirefox-branding-SLE | 31.0-20.1 | SUSE-SU-2016:0338-1 |
| SLES for SAP 12 SP1 | mozilla-nss | 3.20.2-37.1 | SUSE-SU-2016:0338-1 |
| SLES for SAP 12 | MozillaFirefox | 38.6.0esr-57.3 | SUSE-SU-2016:0338-1 |
| SLES for SAP 12 | MozillaFirefox-branding-SLE | 31.0-20.1 | SUSE-SU-2016:0338-1 |
| SLES for SAP 12 | mozilla-nss | 3.20.2-37.1 | SUSE-SU-2016:0338-1 |
| SLES for SAP 11 SP4 | MozillaFirefox | 38.6.0esr-31.3 | SUSE-SU-2016:0334-1 |
| SLES for SAP 11 SP4 | MozillaFirefox-branding-SLED | 38-18.24 | SUSE-SU-2016:0334-1 |
| SLES for SAP 11 SP4 | mozilla-nss | 3.20.2-25.2 | SUSE-SU-2016:0334-1 |
| SLES for SAP 11 SP3 | MozillaFirefox | 38.6.0esr-31.3 | SUSE-SU-2016:0334-1 |
| SLES for SAP 11 SP3 | MozillaFirefox-branding-SLED | 38-18.24 | SUSE-SU-2016:0334-1 |
| SLES for SAP 11 SP3 | mozilla-nss | 3.20.2-25.2 | SUSE-SU-2016:0334-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 50.1.0-1.1 | openSUSE-SU-2024:10071-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Advisories 11
- USN-2973-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-2903-1 nss vulnerability Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-2880-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-427-1 nss - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-480-1 nss - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3688-1 nss - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:0334-1 Security update for MozillaFirefox, MozillaFirefox-branding-SLED, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0584-1 Security update for MozillaFirefox, MozillaFirefox-branding-SLED, MozillaFirefox-branding-SLES-for-VMware, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0338-1 Security update for MozillaFirefox, MozillaFirefox-branding-SLE, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10071-1 MozillaFirefox-50.1.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- 81955 vdb-entry
- DSA-3688 vendor-advisory
- 1034825 vdb-entry
- GLSA-201701-46 vendor-advisory
- http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
- USN-2903-2 vendor-advisory
- USN-2880-1 vendor-advisory
- USN-2903-1 vendor-advisory
- USN-2880-2 vendor-advisory
- https://github.com/hannob/bignum-fuzz/blob/master/CVE-2016-1938-nss-mp_exptmod.c
- https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.21_release_notes
- SUSE-SU-2016:0338 vendor-advisory
- http://www.mozilla.org/security/announce/2016/mfsa2016-07.html
- https://blog.fuzzing-project.org/37-Mozilla-NSS-Wrong-calculation-results-in-mp_div-and-mp_exptmod.html
- USN-2973-1 vendor-advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1194947
- openSUSE-SU-2016:0309 vendor-advisory
- 91787 vdb-entry
- https://github.com/hannob/bignum-fuzz/blob/master/CVE-2016-1938-nss-mp_div.c
- GLSA-201605-06 vendor-advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1190248
- openSUSE-SU-2016:0306 vendor-advisory
- https://hg.mozilla.org/projects/nss/diff/a555bf0fc23a/lib/freebl/mpi/mpi.c