7.5
High
CVE-2026-5947 Undefined behavior may result due to a race condition leading to a use-after-free violation
Description
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| BIND 9 9.21 | 9.21.0 → 9.21.21 | No fix stated |
| BIND 9 9.20 | 9.20.0 → 9.20.22 | No fix stated |
| BIND 9 9.18 | earliest → < 9.18.28 | 9.18.28 |
| Red Hat Hardened Images 9.18 | earliest → < 9.18.48-1.1.hum1 | 9.18.48-1.1.hum1 |
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 6 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published |
Show the other branch Hide the other branch
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat OpenShift Container Platform 4 | Versions not published |
Other CVEs of BIND 9
The 87 CVEs of BIND 9 →
CVE-2026-97313
A recursive BIND server that receives a query with recursion desired (RD=1) followed by a non-recursive query (RD=0) may…
7.5
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CVE-2026-96888
A BIND resolver that is configured with both a "redirect" zone and "qname-minimization strict" may abort with an…
7.5
High
CVE-2026-94300
Replaying GSS-TSIG signed UDP messages can result in memory corruption in "`named`"
8.1
High
CVE-2026-19630
In a BIND resolver, inbound DNS protocol messages with a particular structure will result in additional processing, with…
7.5
High