SB20260610122 - Ubuntu update for openssl
Published: June 10, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 7 vulnerabilities.
1) Out-of-bounds read (CVE-ID: CVE-2026-34180)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to integer truncation in the ASN.1 decoder when parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length. A remote attacker can supply crafted ASN.1 input to disclose sensitive information.
The issue affects only 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected.
2) Input validation error (CVE-ID: CVE-2026-34182)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to bypass integrity validation.
The vulnerability exists due to improper input validation in CMS AuthEnvelopedData processing when decrypting crafted AuthEnvelopedData containers. A remote attacker can send a specially crafted CMS message to bypass integrity validation.
In some cases, if the application exposes decryption success or failure, the issue can be used as an oracle to obtain key-equivalent functionality for the content-encryption key.
3) NULL pointer dereference (CVE-ID: CVE-2026-42766)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to NULL pointer dereference in password-based CMS decryption when processing a specially crafted CMS message with an absent PasswordRecipientInfo.keyDerivationAlgorithm field. A remote attacker can send a specially crafted CMS message to cause a denial of service.
Applications that process password-encrypted CMS messages may be affected.
4) NULL pointer dereference (CVE-ID: CVE-2026-42767)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to NULL pointer dereference in CRMF EncryptedValue decryption when processing a crafted CMP response containing an EncryptedValue structure with an algorithm OID but no parameters field. A remote attacker can send a crafted CMP response to cause a denial of service.
The issue can be triggered by an attacker-controlled CMP server or a man-in-the-middle.
5) Use-after-free (CVE-ID: CVE-2026-45447)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to use-after-free in the PKCS7_verify() function when processing a specially crafted PKCS#7 or S/MIME signed message during PKCS#7 signature verification. A remote attacker can send a specially crafted signed message to execute arbitrary code.
Applications using the CMS APIs for this processing are not affected.
6) Heap-based buffer overflow (CVE-ID: CVE-2026-7383)
CWE-ID: CWE-122 - Heap-based Buffer Overflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to execute arbitrary code.
The vulnerability exists due to heap-based buffer overflow in ASN1_mbstring_copy() and ASN1_mbstring_ncopy() when converting attacker-controlled multibyte strings to Unicode output. A local user can supply extremely large crafted input to execute arbitrary code.
Triggering the issue requires direct use of ASN1_mbstring_copy() or ASN1_mbstring_ncopy(), or a custom string type registered via ASN1_STRING_TABLE_add(), with attacker-controlled input on the order of half a gigabyte or more.
7) Out-of-bounds read (CVE-ID: CVE-2026-9076)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to out-of-bounds read in kek_unwrap_key() when processing attacker-supplied CMS password-based decryption data with a stream-mode KEK cipher. A remote attacker can send a specially crafted CMS message to cause a denial of service.
No password knowledge is required because the over-read occurs during the unwrap attempt before authentication succeeds.
Remediation
Install update from vendor's website.