Description
MapServer is a system for developing web-based GIS applications. From 6.4.0 to before 8.6.3, msSLDParseUserStyle always calls _SLDApplyRuleValues(psRule, psLayer, 1); for any <Rule> carrying <ElseFilter/> — it assumes msSLDParseRule added one class. When the rule has no symbolizer (a structurally valid SLD), msSLDParseRule adds zero, and _SLDApplyRuleValues ends up indexing _class[-1], resulting in a NULL pointer dereference. A 200-byte well-formed SLD via the WMS SLD_BODY= parameter is enough to trigger this, no auth required. This vulnerability is fixed in 8.6.3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| MapServer | MapServer | >= 6.4.0, < 8.6.3 | — |
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 | mapserver | 8.6.3-1 | — |
| Debian 13 | mapserver | No fix yet | — |
| Debian 12 | mapserver | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | mapserver | No fix yet | — |
| Ubuntu 26.04 LTS | mapserver | No fix yet | — |
| Ubuntu 25.10 | mapserver | No fix yet | — |
| Ubuntu 24.04 LTS | mapserver | No fix yet | — |
| Ubuntu 22.04 LTS | mapserver | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | mapserver | No fix yet | — |
| Ubuntu 18.04 LTS | mapserver | No fix yet | — |
| Ubuntu 16.04 LTS | mapserver | No fix yet | — |