diff --git a/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb b/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
index 3a7af56c34..ad79a3bfa8 100644
--- a/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
+++ b/meta-networking/recipes-support/dnsmasq/dnsmasq_2.90.bb
@@ -21,6 +21,7 @@ SRC_URI = "http://www.thekelleys.org.uk/dnsmasq/${@['archive/', ''][float(d.getV
            file://CVE-2026-4893.patch \
            file://CVE-2026-5172.patch \
            file://CVE-2026-2291.patch \
+           file://CVE-2026-4890.patch \
 "
 SRC_URI[sha256sum] = "8f6666b542403b5ee7ccce66ea73a4a51cf19dd49392aaccd37231a2c51b303b"
 
diff --git a/meta-networking/recipes-support/dnsmasq/files/CVE-2026-4890.patch b/meta-networking/recipes-support/dnsmasq/files/CVE-2026-4890.patch
new file mode 100644
index 0000000000..975a80d474
--- /dev/null
+++ b/meta-networking/recipes-support/dnsmasq/files/CVE-2026-4890.patch
@@ -0,0 +1,75 @@
+From 6a185fdd49ee668c75ad7e95461de45c3a3d8d10 Mon Sep 17 00:00:00 2001
+Author: Simon Kelley <simon@thekelleys.org.uk>
+Date:   Fri Apr 10 22:16:45 2026 +0100
+Subject: [PATCH] Fix NSEC bitmap parsing infinite loop. CVE-2026-4890
+
+Report from Royce M <royce@xchglabs.com>.
+
+Location: dnssec.c:1290-1306, dnssec.c:1450-1463
+
+The bitmap window iteration advances by p[1] instead of p[1]+2 (missing the 2-byte window header). With bitmap_length=0, both rdlen and p are
+unchanged, causing an infinite loop and dnsmasq stops responding to all queries.
+
+The same code accesses p[2] after only checking rdlen >= 2 without verifying p[1] >= 1, causing OOB reads at 6 locations.
+
+Both bugs are reachable before RRSIG validation (confirmed by the source comment at line 2125), so no valid DNSSEC signatures are needed.
+
+CVE: CVE-2026-4890
+Upstream-Status: Backport [https://thekelleys.org.uk/dnsmasq/CVE/CVE-2026-4890.dnsmasq-2.91.diff]
+
+Signed-off-by: Benjamin Robin <benjamin.robin@bootlin.com>
+---
+ src/dnssec.c | 14 +++++++-------
+ 1 file changed, 7 insertions(+), 7 deletions(-)
+
+diff --git a/src/dnssec.c b/src/dnssec.c
+index ed2f53ff1763..68f1b5d0fab4 100644
+--- a/src/dnssec.c
++++ b/src/dnssec.c
+@@ -1270,10 +1270,10 @@ static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsi
+ 	     packet checked to be as long as rdlen implies in prove_non_existence() */
+ 	  
+ 	  /* If we can prove that there's no NS record, return that information. */
+-	  if (nons && rdlen >= 2 && p[0] == 0 && (p[2] & (0x80 >> T_NS)) != 0)
++	  if (nons && rdlen >= 2 && p[0] == 0 && p[1] >= 1  && (p[2] & (0x80 >> T_NS)) != 0)
+ 	    *nons = 0;
+ 	  
+-	  if (rdlen >= 2 && p[0] == 0)
++	  if (rdlen >= 2 && p[0] == 0 && p[1] >= 1)
+ 	    {
+ 	      /* A CNAME answer would also be valid, so if there's a CNAME is should 
+ 		 have been returned. */
+@@ -1301,8 +1301,8 @@ static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsi
+ 		  break; /* finished checking */
+ 		}
+ 	      
+-	      rdlen -= p[1];
+-	      p +=  p[1];
++	      rdlen -= p[1] + 2;
++	      p +=  p[1] + 2;
+ 	    }
+ 	  
+ 	  return 0;
+@@ -1429,7 +1429,7 @@ static int check_nsec3_coverage(struct dns_header *header, size_t plen, int dige
+ 		p += hash_len; /* skip next-domain hash */
+ 		rdlen -= p - psave;
+ 
+-		if (rdlen >= 2 && p[0] == 0)
++		if (rdlen >= 2 && p[0] == 0 && p[1] >= 1)
+ 		  {
+ 		    /* If we can prove that there's no NS record, return that information. */
+ 		    if (nons && (p[2] & (0x80 >> T_NS)) != 0)
+@@ -1458,8 +1458,8 @@ static int check_nsec3_coverage(struct dns_header *header, size_t plen, int dige
+ 			break; /* finished checking */
+ 		      }
+ 		    
+-		    rdlen -= p[1];
+-		    p +=  p[1];
++		    rdlen -= p[1] + 2;
++		    p +=  p[1] + 2;
+ 		  }
+ 		
+ 		return 1;
+-- 
+2.55.0
+